SILICON CARBIDE

CAS No: 409-21-2
RTECS No: VW0450000
Molecular Weight 40.1
European Community (EC) Number: 206-991-8

Silicon carbide (SiC), also known as carborundum, is a semiconductor containing silicon and carbon.
Silicon carbide occurs in nature as the extremely rare mineral moissanite.
Synthetic SiC powder has been mass-produced since 1893 for use as an abrasive.
Grains of Silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests.
Large single crystals of silicon carbide can be grown by the Lely method and they can be cut into gems known as synthetic moissanite.
Electronic applications of silicon carbide such as light-emitting diodes (LEDs) and detectors in early radios were first demonstrated around 1907.
SiC is used in semiconductor electronics devices that operate at high temperatures or high voltages, or both.

DEFINATION

Silicon carbide (SiC) is one of the hardest technical ceramics available.
For many years Silicon carbide was second only to diamond on the Mohs scale, and to date, sintered silicon carbide remains both a competitive and supplementary material for abrasive synthetic diamonds.
Combined with Silicon carbides high thermal conductivity and superb corrosion resistant properties, silicon carbide ceramics are workhorse materials for challenging application areas.

Silicon carbide, exceedingly hard, synthetically produced crystalline compound of silicon and carbon.
Silicon carbides chemical formula is SiC.
Since the late 19th century silicon carbide has been an important material for sandpapers, grinding wheels, and cutting tools.
More recently, Silicon carbide has found application in refractory linings and heating elements for industrial furnaces, in wear-resistant parts for pumps and rocket engines, and in semiconducting substrates for light-emitting diodes.

Silicon carbide is a solid industrial mineral crystalline.
Carborundum is used as a semiconductor and a ceramic, commonly referred to as carborundum.
SiC exists naturally in an extremely rare mineral called moissanite.
Pure silicon carbides appear as colourless and transparent crystals.
When impurities are added such as nitrogen or aluminium, silicon carbide crystals appear green or blue depending on the level of impurity.
Carborundum is mostly used for Carborundums hardness and strength, though Carborundums combined ceramic and semiconductor properties make SiC excellent in the manufacturing of fast, high-voltage, and high-temperature devices.

Silicon carbide is an important non-oxide ceramic which has diverse industrial applications.
In fact, CARBORUNDUM has exclusive properties such as high hardness and strength, chemical and thermal stability, high melting point, oxidation resistance,  high  erosion  resistance,  etc.
All of  these qualities make SiC a perfect candidate for high power,  high temperature electronic devices as  well as  abrasion and  cutting applications.
Quite  a lot  of works  were reported  on SiC synthesis since  the  manufacturing process  initiated by  Acheson in 1892.
In  this  chapter, a brief  summary  is  given  for  the  different  SiC  crystal  structures  and  the  most  common encountered polytypes will be cited.
We focus then on the various fabrication routes of SiC starting  from  the  traditional  Acheson  process  which  led  to  a  large  extent  into commercialization of  silicon carbide.
This process is  based on a conventional carbothermal reduction  method  for  the  synthesis  of  SiC  powders. 
Nevertheless,  this  process  involves numerous  steps,  has  an  excessive  demand  for  energy  and  provides  rather  poor  quality materials. 
Several  alternative  methods  have  been  previously  reported  for  the  SiC production. An  overview of  the most  common  used methods  for  SiC elaboration such  as physical vapour deposition (PVT), chemical vapour deposition (CVD), sol-gel, liquid phase sintering  (LPS)  or  mechanical  alloying  (MA)  will  be detailed.
The  resulting  mechanical, structural and electrical properties of the fabricated SiC will be discussed as a function of the synthesis methods.

Silicon carbide (SiC), a semiconductor compound consisting of silicon (Si) and carbon (C), belongs to the wide bandgap (WBG) family of materials.
Carborundums physical bond is very strong, giving the semiconductor a high mechanical, chemical and thermal stability.
The wide band gap and high thermal stability allow SiC devices to be used at junction temperatures higher than those of silicon, even over 200°C.
The main advantage offered by silicon carbide in power applications is CARBORUNDUMs low drift region resistance, which is a key factor for high-voltage power devices.
SiC-based power devices are driving a radical transformation of power electronics, thanks to a combination of excellent physical and electronic properties.
Although the material has been known for a long time, CARBORUNDUMs use as a semiconductor is relatively recent, in great measure due to the availability of large and high-quality wafers.
In recent decades, efforts have focused on developing specific and unique high-temperature crystal growth processes.
Though SiC is available with different polymorphic crystalline structures (also known as polytypes), the 4H-SiC polytype hexagonal crystal structure is the most suitable for high power applications.

Exhibits extremely high hardness
Offers high wear and chemical resistance.
Tribological performance under high load, including pressure, sliding speed, temperature.
Provides corrosion resistance.
Silicon Carbide Materials are used in a wide variety of industries and applications such as sealing components, blasting nozzles, sliding bearings, and flow reactors.
Silicon carbide is an effective material for applications in which wear and corrosion resistance are critical concerns.

At International Syalons, we offer high-performance silicon carbide ceramics via reaction bonding and sintering.
Each manufacturing technique yields a precision zero-porosity ceramic with exceptional resistance to chemical attack and good high-temperature properties.
These result from a robust atomic structure with carbon and silicon forming a strong tetrahedral lattice.
The advantages of this include:
Unmatched hardness (2600 Kg/mm2)
Superior thermal conductivity (150 W/(mK))
Moderate thermal shock resistance (ΔT = 400°C)
Good flexural strength at high temperatures (450 MPa at 1000°C)
Sintered silicon carbide is engineered via conventional means, using non-oxide sintering aids and high-temperature forming process in inert atmospheres.
Reaction bonding differs in that additional silicon is made to infiltrate the green body to form additional SiC grains that bond with the primary ceramic.
The latter is typically used to increase thermal shock resistance.

Explore our Carborundum products below where you will find full specifications and a table detailing comprehensive behaviours in acids and alkalis.
If you would like to learn about specific SiC components, or the industries that we serve, just contact a member of the International Syalons team today.

Artificial silicon carbide (SiC) is included in this database as samples of Carborundum are frequently sold in "rock shops" and on internet auctions, sometimes under the name 'carborundum', sometimes as 'moissanite' (there is a very rare natural silicon carbide mineral with the name moissanite), but most frequently with no name at all.
Carborundum is easily recognised by SILICON CARBIDEs dark blue-black colour, rainbow sheen (like the colours you see on oily water) and the extreme hardness, Carborundum will easily scratch glass and every common mineral except diamond.
Carborundum is formed in blast furnaces during the production of iron.
SiC is also an important high-performance ceramic.

Comprising an ultra-thin layer of crystalline 3C polytype silicon carbide (SiC) in a silicon frame, and available in a wide range of window sizes and membrane thicknesses. These membranes have superior transmission characteristics in the 10 to 20nm wavelength range, and superior transmission in the 1 to 3 nm range, compared to traditional silicon nitride windows. Simulated transmission data is shown below (LBNL CXRO X-Ray database). SiC has a thermal conductivity four times that of the silicon nitride typically used as a membrane material. These membranes are therefore advantageous for applications where uniform heating of the membrane area is required. SiC is a wide band gap semiconductor, and is therefore electrically conductive at room temperature, with resistivity in the range 10-1000 Ωcm.

Available in a 381μm thick frame, with frame sizes of 5mm, 7.5mm and 10mm (other sizes available on request), and with SiC membrane thicknesses from 30nm up to 200nm.
Thin film coatings can be supplied on request (Zr, Fe, Ni, SiO2, Al, Au, Cr, Ti, please inquire for our full range of materials).

Silicon carbide is a man made mineral of extreme hardness and sharpness.
Silicon carbide is the ideal abrasive for grinding / sanding materials of low tensile strength such as Cast Iron, Brass, Aluminum, Bronze etc.
Silicon carbidees thermal properties make SILICON CARBIDE an excellent medium for use in the manufacture of refractory products and crucibles.
Silicon carbide is produced by a process involving the electrochemical reaction of silica – in the form of quartz with Carbon in the form of raw petroleum coke.
The stoichiometric mixture is reacted in an electrical resistance furnace at a temperature greater than 2200?C to yield high quality crystals.
The large crystals are then segregated, crushed, cleaned of magnetic impurities in high intensity magnetic separators and classified into narrow size fractions to suit the end use.
Dedicated lines produce SILICON CARBIDEs for different applications.
Silicon Carbide Grains are also used in marble and granite polishing, manufacture of Kiln furniture and as a deoxidizer in Iron and steel making.

Silicon Carbide is the only chemical compound of carbon and silicon.
Silicon carbide was originally produced by a high temperature electro-chemical reaction of sand and carbon.
Silicon carbide is an excellent abrasive and has been produced and made into grinding wheels and other abrasive products for over one hundred years.
Today the material has been developed into a high quality technical grade ceramic with very good mechanical properties.
Silicon carbide is used in abrasives, refractories, ceramics, and numerous high-performance applications.
The material can also be made an electrical conductor and has applications in resistance heating, flame igniters and electronic components.
Structural and wear applications are constantly developing.

ADVANTAGES OF Silicon carbide
Silicon carbide is mostly used in applications that require high thermal conductivity.
Silicon carbides extreme hardness, resulting extraordinary resistance to wear, and excellent chemical resistance are the distinguishing qualities of this material.
Silicon carbidehas become an irreplaceable cornerstone of chemical process engineering, milling processes and dispersion technology.

Highest temperature tolerance
200°C rated die, reduced cooling system complexity, cost and size
Fewer switches
Reduced losses, improved size, weight and power capabilities
Higher current density
2x Power density at same size and weight
Higher energy band gap
More robust against heat, radiation and electromagnetic disturbances.
Power overlay technology
Ultra-thin profile that enables 40% space savings
2x cooling compared to wire-bonded modules

SiC technology leader
GE has been a leader in SiC technology development for nearly two decades.
From chip design and component engineering to full system implementation, GE has demonstrated class-leading performance in power devices, advanced packaging and power electronics applications.
GE offered the Industry’s first -55 to 200˚C MOSFET.

Discovery.
Silicon carbide was discovered by the American inventor Edward G. Acheson in 1891.
While attempting to produce artificial diamonds, Acheson heated a mixture of clay and powdered coke in an iron bowl, with the bowl and an ordinary carbon arc-light serving as the electrodes.
He found bright green crystals attached to the carbon electrode and thought that he had prepared some new compound of carbon and alumina from the clay.
He called the new compound Carborundum because the natural mineral form of alumina is called corundum.
Finding that the crystals approximated the hardness of diamond and immediately realizing the significance of his discovery, Acheson applied for a U.S. patent.
His early Silicon carbide initially was offered for the polishing of gems and sold at a price comparable with natural diamond dust.
The new compound, which was obtainable from cheap raw materials and in good yields, soon became an important industrial abrasive.
About the same time Acheson made his discovery, Henri Moissan in France produced a similar compound from a mixture of quartz and carbon; but in a publication of 1903, Moissan ascribed the original discovery to Acheson.
Some natural silicon carbide was found in Arizona in the Canyon Diablo meteorite and bears the mineralogical name moissanite.

Modern manufacture

The modern method of manufacturing silicon carbide for the abrasives, metallurgical, and refractories industries is basically the same as that developed by Acheson.
A mixture of pure silica sand and carbon in the form of finely ground coke is built up around a carbon conductor within a brick electrical resistance-type furnace.
Electric current is passed through the conductor, bringing about a chemical reaction in which the carbon in the coke and silicon in the sand combine to form SiC and carbon monoxide gas.
A furnace run can last several days, during which temperatures vary from 2,200° to 2,700° C (4,000° to 4,900° F) in the core to about 1,400° C (2,500° F) at the outer edge. 
he energy consumption exceeds 100,000 kilowatt-hours per run. 
At the completion of the run, the Silicon carbide consists of a core of green to black SiC crystals loosely knitted together, surrounded by partially or entirely unconverted raw material.
The lump aggregate is crushed, ground, and screened into various sizes appropriate to the end use.
For special applications, silicon carbide is produced by a number of advanced processes.
Reaction-bonded silicon carbide is produced by mixing SiC powder with powdered carbon and a plasticizer, forming the mixture into the desired shape, burning off the plasticizer, and then infusing the fired object with gaseous or molten silicon, which reacts with the carbon to form additional SiC.
Wear-resistant layers of SiC can be formed by chemical vapour deposition, a process in which volatile compounds containing carbon and silicon are reacted at high temperatures in the presence of hydrogen.
For advanced electronic applications, large single crystals of SiC can be grown from vapour; the boule can then be sliced into wafers much like silicon for fabrication into solid-state devices.
For reinforcing metals or other ceramics, SiC fibres can be formed in a number of ways, including chemical vapour deposition and the firing of silicon-containing polymer fibres.

Properties and applications.
Until the invention of boron carbide in 1929, silicon carbide was the hardest synthetic material known.
Silicon carbide has a Mohs hardness rating of 9, approaching that of diamond.
In addition to hardness, silicon carbide crystals have fracture characteristics that make them extremely useful in grinding wheels and in abrasive paper and cloth products.
Silicon carbides high thermal conductivity, together with its high-temperature strength, low thermal expansion, and resistance to chemical reaction, makes silicon carbide valuable in the manufacture of high-temperature bricks and other refractories.
Silicon carbide is also classed as a semiconductor, having an electrical conductivity between that of metals and insulating materials.
This property, in combination with SILICON CARBIDEs thermal properties, makes SiC a promising substitute for traditional semiconductors such as silicon in high-temperature applications.

Natural occurrence

Moissanite single crystal (≈1 mm in size)
Naturally occurring moissanite is found in only minute quantities in certain types of meteorite and in corundum deposits and kimberlite.
Virtually all the silicon carbide sold in the world, including moissanite jewels, is synthetic.
Natural moissanite was first found in 1893 as a small component of the Canyon Diablo meteorite in Arizona by Dr. Ferdinand Henri Moissan, after whom the material was named in 1905.
Moissan's discovery of naturally occurring SiC was initially disputed because his sample may have been contaminated by silicon carbide saw blades that were already on the market at that time.
While rare on Earth, silicon carbide is remarkably common in space.
Carborundum is a common form of stardust found around carbon-rich stars, and examples of this stardust have been found in pristine condition in primitive (unaltered) meteorites.
The silicon carbide found in space and in meteorites is almost exclusively the beta-polymorph.
Analysis of SiC grains found in the Murchison meteorite, a carbonaceous chondrite meteorite, has revealed anomalous isotopic ratios of carbon and silicon, indicating that these grains originated outside the solar system.

Many manufacturers are charging forward in using SiC in applications such as electric vehicles, solar energy systems, and data centers.
These efficiency-oriented systems all result in high voltages and high temperatures.
We're seeing a significant global push to implement SiC over other materials in an effort to reduce carbon emissions caused by power inefficiencies at higher voltages.
Although cutting-edge technologies such as electric vehicles and solar energy are pioneering the utilization of SiC, we expect to see more legacy industries follow suit soon.
SiC has become popular in the automotive sector as a result of the industry's demand for high quality, reliability, and efficiency.
SiC can answer high voltage demands with prowess.
Silicon carbide has the potential to increase electric vehicle driving distances by increasing the overall system efficiency, especially within the inverter system, which increases the vehicle's overall energy conservation while reducing the size and resultant weight of battery management systems.
Goldman Sachs even predicts that utilizing silicon carbide in electric vehicles can reduce EV manufacturing cost and cost of ownership by nearly $2,000 per vehicle.
SiC also optimizes EV fast-charging processes, which typically operate in the kV range, where SILICON CARBIDE can reduce overall system loss by almost 30%, increase power density by 30%, and reduce the component count by 30%.
This efficiency will allow fast charging stations to be smaller, faster, and more cost effective.

In the solar industry, SiC-enabled inverter optimization also plays a large role in efficiency and cost savings.
Utilizing silicon carbide in solar inverters increases the system's switching frequency by two to three times that of standard silicon.
This switching frequency increase allows for a reduction in the circuit's magnetics, resulting in considerable space and cost savings.
As a result, silicon carbide-based inverter designs can be nearly half the size and weight than that of a silicon-based inverter.
Another factor that encourages solar manufacturers and engineers to use SiC over other materials, such as gallium nitride, is SILICON CARBIDEs robust durability and reliability.
Silicon carbide's reliability enables solar systems to achieve the stable longevity they need to operate continuously for over a decade.

Wide-scale production

Wide-scale production is credited to Edward Goodrich Acheson in 1890.
Acheson was attempting to prepare artificial diamonds when he heated a mixture of clay (aluminium silicate) and powdered coke (carbon) in an iron bowl.
He called the blue crystals that formed carborundum, believing SILICON CARBIDE to be a new compound of carbon and aluminium, similar to corundum.
Moissan also synthesized SiC by several routes, including dissolution of carbon in molten silicon, melting a mixture of calcium carbide and silica, and by reducing silica with carbon in an electric furnace.
Acheson patented the method for making silicon carbide powder on February 28, 1893.
Acheson also developed the electric batch furnace by which SiC is still made today and formed the Carborundum Company to manufacture bulk SiC, initially for use as an abrasive.
In 1900 the company settled with the Electric Smelting and Aluminum Company when a judge's decision gave "priority broadly" to its founders "for reducing ores and other substances by the incandescent method".
Carborundum is said that Acheson was trying to dissolve carbon in molten corundum (alumina) and discovered the presence of hard, blue-black crystals which he believed to be a compound of carbon and corundum: hence carborundum.
Carborundum may be that he named the material "Carborundum" by analogy to corundum, which is another very hard substance (9 on the Mohs scale).
The first use of SiC was as an abrasive.
This was followed by electronic applications.
In the beginning of the 20th century, silicon carbide was used as a detector in the first radios.
In 1907 Henry Joseph Round produced the first LED by applying a voltage to a SiC crystal and observing yellow, green and orange emission at the cathode.
The effect was later rediscovered by O. V. Losev in the Soviet Union in 1923.

Production

Because natural moissanite is extremely scarce, most silicon carbide is synthetic.
Silicon carbide is used as an abrasive, as well as a semiconductor and diamond simulant of gem quality.
The simplest process to manufacture silicon carbide is to combine silica sand and carbon in an Acheson graphite electric resistance furnace at a high temperature, between 1,600 °C (2,910 °F) and 2,500 °C (4,530 °F).
Fine SiO2 particles in plant material (e.g. rice husks) can be converted to SiC by heating in the excess carbon from the organic material.
The silica fume, which is a byproduct of producing silicon metal and ferrosilicon alloys, can also be converted to SiC by heating with graphite at 1,500 °C (2,730 °F).
The material formed in the Acheson furnace varies in purity, according to its distance from the graphite resistor heat source.
Colorless, pale yellow and green crystals have the highest purity and are found closest to the resistor.
The color changes to blue and black at greater distance from the resistor, and these darker crystals are less pure.
Nitrogen and aluminium are common impurities, and they affect the electrical conductivity of SiC.
Synthetic SiC Lely crystals
Pure silicon carbide can be made by the Lely process,in which SiC powder is sublimed into high-temperature species of silicon, carbon, silicon dicarbide (SiC2), and disilicon carbide (Si2C) in an argon gas ambient at 2500 °C and redeposited into flake-like single crystals, sized up to 2 × 2 cm, at a slightly colder substrate.
This process yields high-quality single crystals, mostly of 6H-SiC phase (because of high growth temperature).
A modified Lely process involving induction heating in graphite crucibles yields even larger single crystals of 4 inches (10 cm) in diameter, having a section 81 times larger compared to the conventional Lely process.
Cubic SiC is usually grown by the more expensive process of chemical vapor deposition (CVD) of silane, hydrogen and nitrogen.
Homoepitaxial and heteroepitaxial SiC layers can be grown employing both gas and liquid phase approaches.
To form complex shaped SiC, preceramic polymers can be used as precursors which form the ceramic product through pyrolysis at temperatures in the range 1000–1100 °C.
Precursor materials to obtain silicon carbide in such a manner include polycarbosilanes, poly(methylsilyne) and polysilazanes.
Silicon carbide materials obtained through the pyrolysis of preceramic polymers are known as polymer derived ceramics or PDCs.
Pyrolysis of preceramic polymers is most often conducted under an inert atmosphere at relatively low temperatures.
Relative to the CVD process, the pyrolysis method is advantageous because the polymer can be formed into various shapes prior to thermalization into the ceramic.
SiC can also be made into wafers by cutting a single crystal either using a diamond wire saw or by using a laser.
SiC is a useful semiconductor used in power electronics.

Historically, manufacturers use silicon carbide in high-temperature settings for devices such as bearings, heating machinery components, car brakes, and even knife sharpening tools.
In electronics and semiconductor applications, SiC's advantage main advantages are:
- High thermal conductivity of 120-270 W/mK
- Low coefficient of thermal expansion of 4.0x10^-6/°C
- High maximum current density
These three characteristics combined give SiC excellent electrical conductivity, especially when compared to silicon, SiC's more popular cousin.
SiC's material characteristics make Carborundum highly advantageous for high power applications where high current, high temperatures, and high thermal conductivity are required.
In recent years, SiC has become a key player in the semiconductor industry, powering MOSFETs, Schottky diodes, and power modules for use in high-power, high-efficiency applications.
While more expensive than silicon MOSFETs, which are typically limited to breakdown voltages at 900V, SiC allows for voltage thresholds at nearly 10kV.
SiC also has very low switching losses and can support high operating frequencies, which allows it to achieve currently unbeatable efficiencies, especially in applications that operate at over 600 volts.
With proper implementation, SiC devices can reduce converter and inverter system losses by nearly 50%, size by 300%, and overall system cost by 20%.
This reduction in overall system size lends SiC the ability to be extremely useful in weight and space-sensitive applications.

Silicon carbide can be found in the mineral moissanite, but CARBORUNDUM is rarely found in nature.
So, Carborundum is synthetically produced by a synthesising technique called the Acheson method, named after CARBORUNDUMs inventor, Edward G. Acheson.
Pure silica (SiO2), or quartz sand, and finely ground petroleum coke (carbon) are mixed and heated in an electric resistive furnace to an elevated temperature of around 1700 to 2500°C.
Here below is the main chemical reaction resulting in the formation of ɑ-SiC:
Silicon carbide develops a cylindrical ingot around the core, forming layers of ɑ-SiC, β-SiC, and an unreacted material on the outside.
ɑ-SiC is the highest grade with a coarse crystalline structure, and β-SiC is the metallurgical grade.
Based on the raw material quality, the SiC can be produced as either green or black.
The SiC ingots are then sorted and processed for the specific application they are intended for.
They may be crushed, milled, or chemically treated to achieve the properties required for utilisation.

Structure and properties

Properties of silicon carbide
Robust crystal structure
Silicon carbide is composed of light elements, silicon (Si) and carbon (C).
Carborundums basic building block is a crystal of four carbon atoms forming a tetrahedron, covalently bonded to a single silicon atom at the centre.
SiC also exhibits polymorphism as Carborundum exists in different phases and crystalline structures.

High hardness
Silicon carbide has a Mohs hardness rating of 9, making CARBORUNDUM the hardest available material next to boron carbide (9.5) and diamond (10).
Carborundum is this apparent property that makes SiC an excellent material choice for mechanical seals, bearings, and cutting tools.

High-temperature resistance
Silicon carbide’s resistance to high temperature and thermal shock is the property that allows SiC to be used in the manufacturing of fire bricks and other refractory materials.
The decomposition of silicon carbide starts at 2000°C.

Conductivity
If SiC is purified, Carborundums behaviour manifests that of an electrical insulator. However, by governing impurities, silicon carbides can exhibit the electrical properties of a semiconductor.
For example, introducing varying amounts of aluminium by doping will yield a p-type semiconductor.
Typically, an industrial-grade SiC has a purity of about 98 to 99.5%.
Common impurities are aluminium, iron, oxygen, and free carbon.

Chemical stability
Silicon carbide is a stable and chemically inert substance with high corrosion resistance even when exposed or boiled in acids (hydrochloric, sulphuric, or hydrofluoric acid) or bases (concentrated sodium hydroxides).
Carborundum is found to react in chlorine, but only at a temperature of 900°C and above.
Silicon carbide will start an oxidation reaction in the air when the temperature is at approximately 850°C to form SiO2.

More  than  200  SiC  polytypes  have  been  found  up  to  date  (Pensl,  Choyke,  1993).
Many authors  proved that  these  polytypes were  dependent on  the seed  orientation.
For a  long time, (Stein et al, 1992;  Stein, Lanig, 1993) had attributed this  phenomenon to the different surface  energies of  Si and  C faces  which  influenced  the formation  of  different  polytypes nuclei.
A listing of the most common polytypes includes 3C, 2H, 4H, 6H, 8H, 9R, 10H, 14H, 15R,19R, 2OH, 21H, and 24R, where (C), (H) and (R) are the three basic cubic, hexagonal and rhombohedral  crystallographic  categories.
In  the  cubic  zinc-blende  structure,  labelled  as  3C-SiC  or  β-SiC,  Si  and  C  occupy  ordered  sites in  a  diamond framework.
In  hexagonal polytypes nH-SiC and rhombohedral polytypes nR-SiC, generally referred to as α-SiC, nSi-C bilayers consisting of C and Si layers stack in the primitive unit cell (Muranaka et al, 2008).
SiC polytypes are differentiated by the stacking sequence of each tetrahedrally bonded Si-C bilayer.
In  fact  the  distinct  polytypes  differ  in  both  band  gap  energies  and  electronic properties.
So the band gap varies with the polytype from 2.3 eV for 3C-SiC to over 3.0 eV for 6H-SiC  to  3.2  eV  for  4H-SiC.
Due  to  its  smaller  band  gap,  3C-SiC  has  many  advantages compared  to  the  other  polytypes,  that  permits  inversion  at  lower  electric  field  strength.
Moreover, the electron Hall mobility is isotropic and higher compared to those of 4H and 6H- polytypes (Polychroniadis  et  al, 2004).
Alpha  silicon carbide (α-SiC) is  the most commonly encountered polymorph; CARBORUNDUM is the stable form at elevated temperature as high as 1700°C and has a hexagonal crystal  structure (similar to Wurtzite).
Among  all the hexagonal structures, 6H-SiC and 4H-SiC are the only SiC polytypes currently available in bulk wafer form.
The  β-SiC  (3C-SiC)  with  a  zinc  blende  crystal  structure  (similar  to  diamond),  is  formed  at temperatures below 1700°C  (Muranaka   et al, 2008).
The number  3 refers to the number  of layers needed for periodicity.
3C-SiC possesses the smallest band gap (~2.4eV) (Humphreys et al,1981), and one of the largest electron mobilities (~800 cm2V-1s-1) in low-doped material (Tachibana et al,  1990) of all the known SiC polytypes.
CARBORUNDUM is not currently available in bulk form, despite bulk growth of 3C-SiC having been  demonstrated in a research environment (Shields  et  al  1994).
Nevertheless,  the  beta  form  has  relatively  few  commercial  uses, although there is now increasing interest in CARBORUNDUMs use as a support for heterogeneous catalysts, owing to CARBORUNDUMs higher surface area compared to the alpha form.

Silicon Carbide Ceramics Structure
There are 250 crystalline forms of silicon carbide.
The polymorphic feature of SiC is a large class of similar crystal structures called polymorphs.
They are variants of the same compound, the same in two dimensions but different in three dimensions.
Therefore, they can be viewed as layers stacked in a specific order.
Silicon Carbide Ceramics Properties
Compound Formula: SiC
Molecular Weight: 40.1
Appearance: Black
Melting Point: 2,730° C (4,946° F) (decomposes)
Density: 3.0 to 3.2 g/cm3
Electrical Resistivity: 1 to 4 10x Ω-m
Poisson's Ratio: 0.15 to 0.21
Specific Heat: 670 to 1180 J/kg-K

Silicon Carbide Ceramics Applications
Until the invention of boron carbide in 1929, silicon carbide was the hardest synthetic material known.
Carborundum has a Mohs hardness rating of 9, approaching that of a diamond.
In addition, SiC crystal has fracture characteristics that make them extremely useful in grinding wheels and in abrasive paper and cloth products.
Carborundums high thermal conductivity, together with its high-temperature strength, low thermal expansion, and resistance to chemical reaction and thermal shock, makes silicon carbide valuable in the manufacture of high-temperature bricks and other refractories.
SiC ceramic is also classed as a semiconductor, having an electrical conductivity between that of metals and insulating materials.
This property, in combination with Carborundums thermal properties, makes SiC a promising substitute for traditional semiconductors such as silicon in high-temperature applications.

Silicon carbide exists in about 250 crystalline forms.
Through the inert atmosphere pyrolysis of preceramic polymers, silicon carbide in a glassy amorphous form is also produced.
The polymorphism of SiC is characterized by a large family of similar crystalline structures called polytypes.
They are variations of the same chemical compound that are identical in two dimensions and differ in the third.
Thus, they can be viewed as layers stacked in a certain sequence.
Alpha silicon carbide (α-SiC) is the most commonly encountered polymorph, and is formed at temperatures greater than 1700 °C and has a hexagonal crystal structure (similar to Wurtzite).
The beta modification (β-SiC), with a zinc blende crystal structure (similar to diamond), is formed at temperatures below 1700 °C.
Until recently, the beta form has had relatively few commercial uses, although there is now increasing interest in CARBORUNDUMs use as a support for heterogeneous catalysts, owing to CARBORUNDUMs higher surface area compared to the alpha form.
Pure SiC is colorless.
The brown to black color of the industrial SILICON CARBIDE results from iron impurities.The rainbow-like luster of the crystals is due to the thin-film interference of a passivation layer of silicon dioxide that forms on the surface.
The high sublimation temperature of SiC (approximately 2700 °C) makes CARBORUNDUM useful for bearings and furnace parts.
Silicon carbide does not melt at any known temperature.
Carborundum is also highly inert chemically.
There is currently much interest in CARBORUNDUMs use as a semiconductor material in electronics, where its high thermal conductivity, high electric field breakdown strength and high maximum current density make it more promising than silicon for high-powered devices.
SiC also has a very low coefficient of thermal expansion (4.0 × 10−6/K) and experiences no phase transitions that would cause discontinuities in thermal expansion.

The advantages of SiC power devices
Power devices based on silicon carbide offer various key benefits over conventional silicon devices.
Their higher voltage and higher frequency capabilities allow greater system efficiency, faster switching, lower losses, and better thermal management.
Ultimately, SiC devices allow smaller and lighter power designs featuring higher power density. 
ST recently completed qualification of CARBORUNDUMs third-generation SiC technology platform.
Planar MOSFETs based on this platform set new industry-leading benchmarks for transistor efficiency, power density, and switching performance.
First Carborundums are now commercially available.
SiC for electric mobility
SiC power devices find application in critical power systems inside electric vehicles, including traction inverters, on-board chargers and in the DC/DC conversion stage.
They also provide significant and efficiency gains in charging stations.
With respect to their silicon-based counterparts, SiC devices offer the following advantages:
Over 600 km longer driving range on an average EV
150 to 200 kg less weight on an average EV
Double the energy from a charging station
Longer battery lifetime due to lower stress
SiC for industrial power and drives
SiC devices benefit industrial applications from motors and robots to various other factory automation systems, as well as in power supplies for servers and solar energy conversion systems.
For industrial contexts, SiC devices can deliver the following benefits with respect to silicon-based devices:
50% lower power losses
Ability to run at five times the frequency
50% reduction in system size and weight
20% reduction in total cost of ownership
SiC-based power devices can operate at up to 200°C junction temperature (limited only by the package), which reduces cooling requirements and allows more compact, more reliable, and more robust solutions.
Existing designs can incorporate the performance and efficiency benefits of SiC devices without major changes, allowing fast development turnaround while keeping the BOM to a minimum.

Properties of major SiC polytypes
Polytype: 3C (β), 4H, 6H (α)
Crystal structure: Zinc blende (cubic), Hexagonal, Hexagonal
Space group: T2d-F43m, C46v-P63mc, C46v-P63mc
Pearson symbol: cF8, hP8, hP12
Lattice constants (Å): 4.3596, 3.0730; 10.053, 3.0810; 15.12
Density (g/cm3): 3.21, 3.21, 3.21
Bandgap (eV): 2.36, 3.23, 3.05
Bulk modulus (GPa): 250, 220, 220
Thermal conductivity (W⋅m−1⋅K−1)
@ 300 K (see for temp. dependence): 360, 370, 490

Properties    Si    4H-SiC    GaAs    GaN
Crystal Structure: Diamond    Hexagonal    Zincblende    Hexagonal
Energy Gap: EG(eV): 1.12    3.26    1.43    3.5
Electron Mobility: µn(cm2/VS)    1400    900    8500    1250
Hole Mobility: µp(cm2)    600    100    400    200
Breakdown Field: EB(V/cm)X106    0.3    3    0.4    3
Thermal Conductivity(W/cm?): 1.5    4.9    0.5    1.3
Saturation Drift Velocity: vs(cm/s)X107    1    2.7    2    2.7
Relative Dielectric Constant: eS    11.8    9.7    12.8    9.5
p. n Control    ?    ?    ?    ?
Thermal Oxide    ?    ?    ×    ×

Silicon Carbide Properties (Theoretical)
Compound Formula: Si
Molecular Weight: 40.1
Appearance: Colorless crystals
Melting Point: 2,730° C (4,946° F) (decomposes)
Boiling Point: N/A
Density: 3.0 to 3.2 g/cm3
Solubility in H2O: N/A
Electrical Resistivity: 1 to 4 10x Ω-m
Poisson's Ratio: 0.15 to 0.21
Specific Heat: 670 to 1180 J/kg-K
Tensile Strength: 210 to 370 MPa (Ultimate)
Thermal Conductivity: 120 to 170 W/m-K
Thermal Expansion: 4.0 to 4.5 µm/m-K
Young's Modulus: 370 to 490 GPa
Exact Mass: 39.976927
Monoisotopic Mass: 39.976927

Property: Minimum Value (S.I.)    Maximum Value (S.I.)    Units (S.I.)    Minimum Value (Imp.)    Maximum Value (Imp.)    Units (Imp.)
Atomic Volume (average): 0.01    0.011    m3/kmol    610.237    671.261    in3/kmol
Density: 4.36    4.84    Mg/m3    272.186    302.152    lb/ft3
Energy Content: 750    1250    MJ/kg    81254    135423    kcal/lb
Bulk Modulus: 100    176    GPa    14.5038    25.5266    106 psi
Compressive Strength: 130    1395    MPa    18.8549    202.328    ksi
Ductility: 0.01    0.4        0.01    0.4    NULL
Elastic Limit: 172    1245    MPa    24.9465    180.572    ksi
Endurance Limit: 175    705    MPa    25.3816    102.252    ksi
Fracture Toughness: 14    120    MPa.m1/2    12.7407    109.206    ksi.in1/2
Hardness: 600    3800    MPa    87.0227    551.144    ksi
Loss Coefficient: 0.0001    0.005        0.0001    0.005    NULL
Modulus of Rupture: 130    1300    MPa    18.8549    188.549    ksi
Poisson's Ratio: 0.35    0.37        0.35    0.37    NULL
Shear Modulus: 32    51    GPa    4.64121    7.39692    106 psi
Tensile Strength: 240    1625    MPa    34.8091    235.686    ksi
Young's Modulus: 90    137    GPa    13.0534    19.8702    106 psi
Glass Temperature:  K            °F
Latent Heat of Fusion: 360    370    kJ/kg    154.771    159.071    BTU/lb
Maximum Service Temperature: 570    970    K    566.33    1286.33    °F
Melting Point: 1750    1955    K    2690.33    3059.33    °F
Minimum Service Temperature: 0    0    K    -459.67    -459.67    °F
Specific Heat: 510    650    J/kg.K    0.394668    0.503008    BTU/lb.F
Thermal Conductivity: 3.8    20.7    W/m.K    7.11373    38.7511    BTU.ft/h.ft2.F
Thermal Expansion: 7.9    11    10-6/K    14.22    19.8    10-6/°F
Breakdown Potential: MV/m            V/mil
Dielectric Constant: NULL
Resistivity: 41.7    202    10-8 ohm.m    41.7    202    10-8 ohm.m

Key Silicon Carbide Properties
Low density
High strength
Low thermal expansion
High thermal conductivity
High hardness
High elastic modulus
Excellent thermal shock resistance
Superior chemical inertness

Electrical conductivity
Silicon carbide is a semiconductor, which can be doped n-type by nitrogen or phosphorus and p-type by beryllium, boron, aluminium, or gallium.
Metallic conductivity has been achieved by heavy doping with boron, aluminium or nitrogen.
Superconductivity has been detected in 3C-SiC:Al, 3C-SiC:B and 6H-SiC:B at the same temperature of 1.5 K.
A crucial difference is however observed for the magnetic field behavior between aluminium and boron doping: SiC:Al is type-II, same as SiC:B.
On the contrary, SiC:B is type-I.
In an attempt to explain this difference, CARBORUNDUM was noted that Si sites are more important than carbon sites for superconductivity in SiC.
Whereas boron substitutes carbon in SiC, Al substitutes Si sites.
Therefore, Al and B "see" different environments that might explain different properties of SiC:Al and SiC:B.

Abrasive and cutting tools

In the arts, silicon carbide is a popular abrasive in modern lapidary due to the durability and low cost of the material.
In manufacturing, CARBORUNDUM is used for CARBORUNDUMs hardness in abrasive machining processes such as grinding, honing, water-jet cutting and sandblasting.
Particles of silicon carbide are laminated to paper to create sandpapers and the grip tape on skateboards.
In 1982 an exceptionally strong composite of aluminium oxide and silicon carbide whiskers was discovered.
Development of this laboratory-produced composite to a commercial SILICON CARBIDE took only three years.
In 1985, the first commercial cutting tools made from this alumina and silicon carbide whisker-reinforced composite were introduced into the market.

Structural material

In the 1980s and 1990s, silicon carbide was studied in several research programs for high-temperature gas turbines in Europe, Japan and the United States.
The components were intended to replace nickel superalloy turbine blades or nozzle vanes.
However, none of these projects resulted in a production quantity, mainly because of its low impact resistance and its low fracture toughness.
Like other hard ceramics (namely alumina and boron carbide), silicon carbide is used in composite armor (e.g. Chobham armor), and in ceramic plates in bulletproof vests.
Dragon Skin, which was produced by Pinnacle Armor, used disks of silicon carbide.
Improved fracture toughness in SiC armor can be facilitated through the phenomenon of abnormal grain growth or AGG.
The growth of abnormally long silicon carbide grains may serve to impart a toughening effect through crack-wake bridging, similar to whisker reinforcement.
Similar AGG-toughening effects have been reported in Silicon nitride (Si3N4).
Silicon carbide is used as a support and shelving material in high temperature kilns such as for firing ceramics, glass fusing, or glass casting.
SiC kiln shelves are considerably lighter and more durable than traditional alumina shelves.
In December 2015, infusion of silicon carbide nano-particles in molten magnesium was mentioned as a way to produce a new strong and plastic alloy suitable for use in aeronautics, aerospace, automobile and micro-electronics.

Automobile parts

Silicon-infiltrated carbon-carbon composite is used for high performance "ceramic" brake disks, as they are able to withstand extreme temperatures.
The silicon reacts with the graphite in the carbon-carbon composite to become carbon-fiber-reinforced silicon carbide (C/SiC).
These brake disks are used on some road-going sports cars, supercars, as well as other performance cars including the Porsche Carrera GT, the Bugatti Veyron, the Chevrolet Corvette ZR1, the McLaren P1, Bentley, Ferrari, Lamborghini and some specific high-performance Audi cars.
Silicon carbide is also used in a sintered form for diesel particulate filters.
CARBORUNDUM's also used as an oil additive[dubious – discuss][clarification needed] to reduce friction, emissions, and harmonics.

Electric systems
The earliest electrical application of SiC was in lightning arresters in electric power systems. These devices must exhibit high resistance until the voltage across them reaches a certain threshold VT at which point their resistance must drop to a lower level and maintain this level until the applied voltage drops below VT.

CARBORUNDUM was recognized early on[when?] that SiC had such a voltage-dependent resistance, and so columns of SiC pellets were connected between high-voltage power lines and the earth.
When a lightning strike to the line raises the line voltage sufficiently, the SiC column will conduct, allowing strike current to pass harmlessly to the earth instead of along the power line.
The SiC columns proved to conduct significantly at normal power-line operating voltages and thus had to be placed in series with a spark gap.
This spark gap is ionized and rendered conductive when lightning raises the voltage of the power line conductor, thus effectively connecting the SiC column between the power conductor and the earth.
Spark gaps used in lightning arresters are unreliable, either failing to strike an arc when needed or failing to turn off afterwards, in the latter case due to material failure or contamination by dust or salt.
Usage of SiC columns was originally intended to eliminate the need for the spark gap in lightning arresters.
Gapped SiC arresters were used for lightning-protection and sold under the GE and Westinghouse brand names, among others.
The gapped SiC arrester has been largely displaced by no-gap varistors that use columns of zinc oxide pellets.

Electronic circuit elements
Silicon carbide was the first commercially important semiconductor material.
A crystal radio "carborundum" (synthetic silicon carbide) detector diode was patented by Henry Harrison Chase Dunwoody in 1906.
CARBORUNDUM found much early use in shipboard receivers.

Power electronic devices
SILICON CARBIDE is a semiconductor in research and early mass production providing advantages for fast, high-temperature and/or high-voltage devices.
The first devices available were Schottky diodes, followed by junction-gate FETs and MOSFETs for high-power switching.
Bipolar transistors and thyristors are currently developed.
A major problem for SiC commercialization has been the elimination of defects: edge dislocations, screw dislocations (both hollow and closed core), triangular defects and basal plane dislocations.
As a result, devices made of SiC crystals initially displayed poor reverse blocking performance, though researchers have been tentatively finding solutions to improve the breakdown performance.
Apart from crystal quality, problems with the interface of SiC with silicon dioxide have hampered the development of SiC-based power MOSFETs and insulated-gate bipolar transistors.
Although the mechanism is still unclear, nitriding has dramatically reduced the defects causing the interface problems.
In 2008, the first commercial JFETs rated at 1200 V were introduced to the market, followed in 2011 by the first commercial MOSFETs rated at 1200 V.
JFETs are now available rated 650 V to 1700 V with resistance as low as 25 mΩ.
Beside SiC switches and SiC Schottky diodes (also Schottky barrier diode, SBD) in the popular TO-247 and TO-220 packages, companies started even earlier to implement the bare chips into their power electronic modules.
SiC SBD diodes found wide market spread being used in PFC circuits and IGBT power modules.
Conferences such as the International Conference on Integrated Power Electronics Systems (CIPS) report regularly about the technological progress of SiC power devices.
Major challenges for fully unleashing the capabilities of SiC power devices are:
Gate drive: SiC devices often require gate drive voltage levels that are different from their silicon counterparts and may be even unsymmetric, for example, +20 V and −5 V.
Packaging: SiC chips may have a higher power density than silicon power devices and are able to handle higher temperatures exceeding the silicon limit of 150 °C.
New die attach technologies such as sintering are required to efficiently get the heat out of the devices and ensure a reliable interconnection.

Ultraviolet LED
LEDs
The phenomenon of electroluminescence was discovered in 1907 using silicon carbide and the first commercial LEDs were based on SiC.
Yellow LEDs made from 3C-SiC were manufactured in the Soviet Union in the 1970s[64] and blue LEDs (6H-SiC) worldwide in the 1980s.
LED production soon stopped when a different material, gallium nitride, showed 10–100 times brighter emission.
This difference in efficiency is due to the unfavorable indirect bandgap of SiC, whereas GaN has a direct bandgap which favors light emission.
SiC is still one of the important LED components – SILICON CARBIDE is a popular substrate for growing GaN devices, and SILICON CARBIDE also serves as a heat spreader in high-power LEDs.

Astronomy

The low thermal expansion coefficient, high hardness, rigidity and thermal conductivity make silicon carbide a desirable mirror material for astronomical telescopes.
The growth technology (chemical vapor deposition) has been scaled up to produce disks of polycrystalline silicon carbide up to 3.5 m (11 ft) in diameter, and several telescopes like the Herschel Space Telescope are already equipped with SiC optics, as well the Gaia space observatory spacecraft subsystems are mounted on a rigid silicon carbide frame, which provides a stable structure that will not expand or contract due to heat.
Thin filament pyrometry
Main article: Thin filament pyrometry
Test flame and glowing SiC fibers.
The flame is about 7 cm (2.8 in) tall.
Silicon carbide fibers are used to measure gas temperatures in an optical technique called thin filament pyrometry.
SILICON CARBIDE involves the placement of a thin filament in a hot gas stream.
Radiative emissions from the filament can be correlated with filament temperature.
Filaments are SiC fibers with a diameter of 15 micrometers, about one fifth that of a human hair.
Because the fibers are so thin, they do little to disturb the flame and their temperature remains close to that of the local gas.
Temperatures of about 800–2500 K can be measured.

Heating elements
References to silicon carbide heating elements exist from the early 20th century when they were produced by Acheson's Carborundum Co. in the U.S. and EKL in Berlin.
Silicon carbide offered increased operating temperatures compared with metallic heaters
Silicon carbide elements are used today in the melting of glass and non-ferrous metal, heat treatment of metals, float glass production, production of ceramics and electronics components, igniters in pilot lights for gas heaters, etc.
Nuclear fuel particles and cladding
Silicon carbide is an important material in TRISO-coated fuel particles, the type of nuclear fuel found in high temperature gas cooled reactors such as the Pebble Bed Reactor.
A layer of silicon carbide gives coated fuel particles structural support and is the main diffusion barrier to the release of fission SILICON CARBIDEs.
Silicon carbide composite material has been investigated for use as a replacement for Zircaloy cladding in light water reactors.
One of the reasons for this investigation is that, Zircaloy experiences hydrogen embrittlement as a consequence of the corrosion reaction with water.
This produces a reduction in fracture toughness with increasing volumetric fraction of radial hydrides.
This phenomenon increases drastically with increasing temperature to the detriment of the material.
Silicon carbide cladding does not experience this same mechanical degradation, but instead retains strength properties with increasing temperature.
The composite consists of SiC fibers wrapped around a SiC inner layer and surrounded by an SiC outer layer.
Problems have been reported with the ability to join the pieces of the SiC composite.

Jewelry

A moissanite engagement ring
As a gemstone used in jewelry, silicon carbide is called "synthetic moissanite" or just "moissanite" after the mineral name.
Moissanite is similar to diamond in several important respects: SILICON CARBIDE is transparent and hard (9–9.5 on the Mohs scale, compared to 10 for diamond), with a refractive index between 2.65 and 2.69 (compared to 2.42 for diamond).
Moissanite is somewhat harder than common cubic zirconia.
Unlike diamond, moissanite can be strongly birefringent.
For this reason, moissanite jewels are cut along the optic axis of the crystal to minimize birefringent effects.
SILICON CARBIDE is lighter (density 3.21 g/cm3 vs. 3.53 g/cm3), and much more resistant to heat than diamond.
This results in a stone of higher luster, sharper facets, and good resilience.
Loose moissanite stones may be placed directly into wax ring moulds for lost-wax casting, as can diamond, as moissanite remains undamaged by temperatures up to 1,800 °C (3,270 °F).
Moissanite has become popular as a diamond substitute, and may be misidentified as diamond, since its thermal conductivity is closer to diamond than any other substitute.
Many thermal diamond-testing devices cannot distinguish moissanite from diamond, but the gem is distinct in its birefringence and a very slight green or yellow fluorescence under ultraviolet light.
Some moissanite stones also have curved, string-like inclusions, which diamonds never have.

Steel production

Piece of silicon carbide used in steel making
Silicon carbide, dissolved in a basic oxygen furnace used for making steel, acts as a fuel.
The additional energy liberated allows the furnace to process more scrap with the same charge of hot metal.
SILICON CARBIDE can also be used to raise tap temperatures and adjust the carbon and silicon content.
Silicon carbide is cheaper than a combination of ferrosilicon and carbon, produces cleaner steel and lower emissions due to low levels of trace elements, has a low gas content, and does not lower the temperature of steel.

Catalyst support
The natural resistance to oxidation exhibited by silicon carbide, as well as the discovery of new ways to synthesize the cubic β-SiC form, with SILICON CARBIDEs larger surface area, has led to significant interest in its use as a heterogeneous catalyst support.
This form has already been employed as a catalyst support for the oxidation of hydrocarbons, such as n-butane, to maleic anhydride.
Carborundum printmaking
Silicon carbide is used in carborundum printmaking – a collagraph printmaking technique.
Carborundum grit is applied in a paste to the surface of an aluminium plate.
When the paste is dry, ink is applied and trapped in its granular surface, then wiped from the bare areas of the plate.
The ink plate is then printed onto paper in a rolling-bed press used for intaglio printmaking.
The result is a print of painted marks embossed into the paper.
Carborundum grit is also used in stone Lithography.
SILICON CARBIDEs uniform particle size allows SILICON CARBIDE to be used to "Grain" a stone which removes the previous image.
In a similar process to sanding, coarser grit Carborundum is applied to the stone and worked with a Levigator, then gradually finer and finer grit is applied until the stone is clean.
This creates a grease sensitive surface.

Graphene production
Silicon carbide can be used in the production of graphene because of its chemical properties that promote the epitaxial production of graphene on the surface of SiC nanostructures.
When it comes to SILICON CARBIDEs production, silicon is used primarily as a substrate to grow the graphene.
But there are actually several methods that can be used to grow the graphene on the silicon carbide.
The confinement controlled sublimation (CCS) growth method consists of a SiC chip that is heated under vacuum with graphite.
Then the vacuum is released very gradually to control the growth of graphene.
This method yields the highest quality graphene layers.
But other methods have been reported to yield the same SILICON CARBIDEas well.
Another way of growing graphene would be thermally decomposing SiC at a high temperature within a vacuum.
But this method turns out to yield graphene layers that contain smaller grains within the layers.
So there have been efforts to improve the quality and yield of graphene.
One such method is to perform ex situ graphitization of silicon terminated SiC in an atmosphere consisting of argon.
This method has proved to yield layers of graphene with larger domain sizes than the layer that would be attainable via other methods.
This new method can be very viable to make higher quality graphene for a multitude of technological applications.
When it comes to understanding how or when to use these methods of graphene production, most of them mainly produce or grow this graphene on the SiC within a growth enabling environment.
Silicon carbide is utilized most often at rather higher temperatures (such as 1300˚C) because of SiC thermal properties.
There have been certain procedures that have been performed and studied that could potentially yield methods that use lower temperatures to help manufacture graphene.
More specifically this different approach to graphene growth has been observed to produce graphene within a temperature environment of around 750˚C.
This method entails the combination of certain methods like chemical vapor deposition (CVD) and surface segregation.
And when SILICON CARBIDE comes to the substrate, the procedure would consist of coating a SiC substrate with thin films of a transition metal.
And after the rapid heat treating of this substance, the carbon atoms would then become more abundant at the surface interface of the transition metal film which would then yield graphene.
And this process was found to yield graphene layers that were more continuous throughout the substrate surface.

Quantum physics
Silicon carbide can host point defects in the crystal lattice which are known as color centers.
These defects can produce single photons on demand and thus serve as a platform for single-photon source.
Such a device is a fundamental resource for many emerging applications of quantum information science.
If one pumps a color center via an external optical source or electrical current, the color center will be brought to the excited state and then relax with the emission of one photon.
One well known point defect in silicon carbide is the divacancy which has a similar electronic structure as the nitrogen-vacancy center in diamond.
In 4H-SiC, the divacancy has four different configurations which correspond to four zero-phonon lines (ZPL).
These ZPL values are written using the notation VSi-VC and the unit eV: hh(1.095), kk(1.096), kh(1.119), and hk(1.150).

Fishing rod guides
Silicon carbide is used in the manufacturing of fishing guides because of its durability and wear resistance.
Silicon Carbide rings are fit into a guide frame, typically made from stainless steel or titanium which keep the line from touching the rod blank.
The rings provide a low friction surface which improves casting distance while providing adequate hardness that prevents abrasion from braided fishing line.

Ceramics materials
Silicon carbide (SiC) is a synthetic, semiconducting fine ceramic that excels in a wide cross-section of industrial markets.
Manufacturers benefit from an eclectic offering of silicon carbide grades due to the availability of both high-density and open porous structures.
Combined with the material’s outstanding high-temperature strength and thermal shock resistance, alongside inherently impressive mechanical properties, silicon carbide is one of the most versatile refractory ceramics worldwide.

Silicon Carbide: Grades, Formats & Bonding Types
Saint-Gobain has spent years developing a uniquely broad understanding of the thermomechanical and chemical properties of silicon carbide ceramics developed via numerous distinct manufacturing avenues.
As a result, Saint-Gobain has now positioned itself as one of the foremost silicon carbide ceramic suppliers worldwide.
With a selection of industry-trusted SILICON CARBIDEs on offer, Saint-Gobain routinely services demanding application areas with uniquely tailored solutions.

SILICON CARBIDE (SiC) Technology Benefits
SiC devices have a 10x higher dielectric breakdown field strength, 2x higher electron saturation velocity, 3x higher energy band gap, and 3x higher thermal conductivity compared to Silicon devices.

High Reliability
onsemi SiC devices have a patented termination structure which provides superior robustness for harsh environmental conditions.
H3TRB Testing (High Temp/Humidity/Bias), 85C/85% RH/85% V (960V).

Robustness
onsemi Schottky Barrier SiC Diodes always maintain the best in class behavior in regards to leakage.

Ruggedness
SiC Diodes Ruggedness – Surge and Avalanche

Surge current waveform of a 650V/30A onsemi SiC diode
Avalanche current waveform of a 650V/30A onsemi SiC diode

Silicon Carbide (SiC): History and Applications

They are used more for operation with wear at low temperature than for high temperature behavior.
SiC applications are such as sandblasting injectors, automotive water pump seals, bearings, pump components, and extrusion dies that use high hardness, abrasion resistance, and corrosion resistance of carbide of silicon.

Contributed By Digi-Key Electronics

The only compound of silicon and carbon is silicon carbide (SiC), or carborundum.
SiC does occur naturally as the mineral moissanite, but this is extremely rare.
Silicon carbide has been mass produced in powder form for use as an abrasive since 1893.
As an abrasive, SILICON CARBIDE has been used for over one hundred years in grinding wheels and many other abrasive applications.
With today’s technology, high-quality technical grade ceramics have been developed with SiC which exhibit very advantageous mechanical properties such as:

Exceptional hardness
High strength
Low density
High elastic modulus
High thermal shock resistance
Superior chemical inertness
High thermal conductivity
Low thermal expansion
These high strength and very durable ceramics are widely used in applications such as automotive brakes and clutches along with ceramic plates embedded in bulletproof vests.
Silicon carbide is also used in semiconductor electronic devices operating at high temperatures and/or high voltages such as flame igniters, resistance heating, and harsh environment electronic components.

Automotive uses of SiC
One of the primary uses of silicon carbide is high performance "ceramic" brake discs.
The silicon combines with the graphite in the composite to become carbon-fiber-reinforced silicon carbide (C/SiC).
These brake discs are used on some sports cars, supercars, and other performance vehicles.
Another automotive use of SiC is as an oil additive.
In this application, SiC reduces friction, emissions, and harmonics.

Early uses of SiC
LEDs
Electroluminescence was first discovered in 1907 using silicon carbide light emitting diodes (LEDs).
Shortly thereafter, the first commercial LEDs produced were SiC-based.
The Soviet Union manufactured yellow SiC LEDs in the 1970s while blue ones were manufactured in the 1980s worldwide.
Then, with the introduction of gallium nitride (GaN) LEDs, which can produce ten to one hundred times brighter emissions, SiC LED production was all but halted.
Nevertheless, SiC is still a popular substrate for GaN devices and SILICON CARBIDE is also utilized as a high-power LED heat spreader.

Lightning arresters
SiC has a high resistance until a threshold voltage (VT) is reached, at which point SILICON CARBIDEs resistance drops to a much lower value until the applied voltage drops below VT.
One of the earliest SiC electrical applications that took advantage of this property was lightning arresters in electric power distribution systems

Silicon Carbide Typical Uses
Fixed and moving turbine components
Suction box covers
Seals, bearings
Ball valve parts
Hot gas flow liners
Heat exchangers
Semiconductor process equipment

In recent years silicon carbide, SiC, has re-emerged as a vital technological material that is crucial in many materials and engineering applications.
Interestingly, SiC is one of the few minerals that were first created synthetically and subsequently discovered in nature.
Silicon carbide was first artificially synthesized in 1891 by Edward Acheson as a result of unexpectedly discovering small black crystals of SiC in an electrically heated melt of carbon and alumina.
The subsequent refinement of this technique (the so-called Acheson process) led to the commercial SILICON CARBIDEion of large volumes of small SiC crystals (ground into powder form) for use as an industrial abrasive.
In 1905, silicon carbide was observed in SILICON CARBIDEs natural form by the Nobel-prize-winning chemist Henri Moissan in Diablo Canyon, Arizona.
The transparent mineral, now known as moissanite, is almost as brilliant and as hard as diamond, and is therefore often used as a gemstone.
To date, no large natural deposits of SiC have ever been found in nature so all SiC used today is synthetic.
In the present day, SiC is one of the most widely used materials that plays a critical role in industries such as: aerospace, electronics, industrial furnaces and wear-resistant mechanical parts among others.
Although SiC is widely used in electronics and other high technology applications, the metallurgical, abrasive, and refractory industries are dominating by volume.

1. What are the main properties of SiC?
The combination of silicon with carbon provides this material with excellent mechanical, chemical and thermal properties, including:
high thermal conductivity
low thermal expansion and excellent thermal shock resistance
low power and switching losses
high energy efficiency
high operating frequency and temperature (operating up to 200°C junction)
small die size (with the same breakdown voltage)
intrinsic body diode (MOSFET device)
excellent thermal management which reduces cooling requirements
long lifetime

2. Which are the applications of SiC in electronics?
Silicon carbide is a semiconductor that is perfectly suited to power applications, thanks above all to SILICON CARBIDEs ability to withstand high voltages, up to ten times higher than those usable with silicon.
Semiconductors based on silicon carbide offer higher thermal conductivity, higher electron mobility, and lower power losses.
SiC diodes and transistors can also operate at higher frequencies and temperatures without compromising reliability.
The main applications of SiC devices, such as Schottky diodes and FET/MOSFET transistors, include converters, inverters, power supplies, battery chargers and motor control systems.

3. Why SiC overcomes Si in power applications?
Despite being the most widely used semiconductor in electronics, silicon is beginning to show some limitations, especially in high-power applications.
A relevant factor in these applications is the bandgap, or energy gap, offered by the semiconductor.
When the bandgap is high, the electronics it uses can be smaller, run faster, and more reliably.
SILICON CARBIDE can also operate at higher temperatures, voltages, and frequencies than other semiconductors.
While silicon has a bandgap of around 1.12eV, silicon carbide has a nearly three times greater value of around 3.26eV.

4. Why can SiC handle so high voltages?
Power devices, especially MOSFETs, must be able to handle extremely high voltages.
Thanks to a dielectric breakdown intensity of the electric field about ten times higher than that of silicon, SiC can reach a very high breakdown voltage, from 600V to a few thousand volts.
SiC can use higher doping concentrations than silicon, and the drift layers can be made very thin.
The thinner the drift layer, the lower SILICON CARBIDEs resistance.
In theory, given a high voltage, the resistance of the drift layer per unit area can be reduced to 1/300 of that of silicon.

5. Why SiC can outperform IGBT at high frequencies?
In high-power applications, IGBTs and bipolar transistors have mostly been used in the past, with the aim of reducing the turn-on resistance that occurs at high breakdown voltages.
These devices, however, offer significant switching losses, resulting in heat generation issues that limit their use at high frequencies.
Using SiC, SILICON CARBIDE is possible to make devices, such as Schottky barrier diodes and MOSFETs, which achieve high voltages, low turn-on resistance and fast operation.

6. Which impurities are used to dope SiC material?
In SILICON CARBIDEs pure form, silicon carbide behaves like an electrical insulator.
With the controlled addition of impurities or dopants, SiC can behave like a semiconductor.
A P-type semiconductor can be obtained by doping SILICON CARBIDE with aluminum, boron, or gallium, while impurities of nitrogen and phosphorus give rise to a N-type semiconductor.
Silicon carbide has the ability to conduct electricity under some conditions but not in others, based on factors such as the voltage or intensity of infrared radiation, visible light, and ultraviolet rays.
Unlike other materials, silicon carbide is capable of controlling the P-type and N-type regions required for device fabrication over wide ranges.
For these reasons, SiC is a material suitable for power devices and able to overcome the limitations offered by silicon.

7. How can SiC achieve better thermal management than silicon?
Another important parameter is the thermal conductivity, which is an index of how the semiconductor is able to dissipate the heat it generates. 
f a semiconductor is not able to dissipate heat effectively, a limitation is introduced on the maximum operating voltage and temperature that the device can withstand.
This is another area where silicon carbide outperforms silicon: the thermal conductivity of silicon carbide is 1490 W/m-K, compared to the 150 W/m-K offered by silicon.

8. How is SiC reverse recover time compared to Si-MOSFET?
SiC MOSFETs, like their silicon counterparts, have an internal body diode.
One of the main limitations offered by the body diode is the undesired reverse recovery behavior, which occurs when the diode switches off while carrying a positive forward current.
The reverse recovery time (trr) thus becomes an important index to define the characteristics of a MOSFET.

9. Why is soft turnoff important for short circuit protection?
Another important parameter for a SiC MOSFET is the short circuit withstand time (SCWT).
Since SiC MOSFETs occupy a very small area of the chip and have a high current density, their ability to withstand short circuits that can cause thermal breaks tends to be lower than that of silicon-based devices.
In the case, for example, of a 1.2kV MOSFET with TO247 package, the short-circuit withstand time at Vdd=700V and Vgs=18V is about 8-10 μs.
As Vgs decreases, the saturation current decreases and the withstand time increases.
As Vdd decreases, less heat is generated and the withstand time is longer.
Since the time required to turn off a SiC MOSFET is extremely short, when the turnoff rate Vgs is high, a high dI/dt can cause severe voltage spikes.
A soft turnoff should therefore be used to gradually lower the gate voltage, avoiding overvoltage peaks.

10. Why is isolated gate driver a better choice?
Many electronic devices are both low and high voltage circuits, interconnected to each other to perform control and power functions.
A traction inverter, for example, typically includes a low voltage primary side (power, communication, and control circuits) and a secondary side (high voltage circuits, motor, power stage and auxiliary circuits).
The controller located on the primary side normally uses feedback signals from the high voltage side and is susceptible to possible damage if no isolation barrier is present.
An isolation barrier electrically isolates the circuits from the primary to the secondary side forming separate ground references, implementing the so-called galvanic isolation.
This prevents unwanted AC or DC signals from being transferred from one side to the other, resulting in damage to the power components.

CRYSTAL STRUCTURE
Silicon carbide has a layered crystal structure which occurs in a number of different forms or polytypes.
Composed of carbon and silicon, in equal amounts, each atom is bonded to four atoms of the opposite type in a tetrahedral bonding configuration.
There are three possible arrangements of atoms in a layer of SiC crystal known as the A, B and C positions, and each polytype has the same layers but a different stacking sequence.
As a given layer may be stacked on top of another in a variety of orientations (with both lateral translations and rotations being feasible energetically), silicon carbide may occur in a wide variety of stacking sequences—each unique stacking sequence generating a different polytype (e.g., cubic, hexagonal and rhombohedral structures can all occur).
The hexagonal and rhombohedral structures, designated as the α-form (noncubic), may crystallize in a large number of polytypes whilst, to date, only one form of cubic structure (designated as the β-form) has been recorded.
DesignatioN is by the number of layers in the sequence, followed by H, R, or C to indicate whether the type belongs to the hexagonal, rhombohedral, or cubic class.
To date, over 215 polytypes have been recorded— although only a limited number are of interest technologically (principally the 4H and 6H hexagonal plus the 3C cubic forms).
This interest is driven by the commercial availability of substrates and the low mobility anisotropy (difference in carrier mobility with crystallographic direction) for these polytypes.

Stacking sequences of the Crystal structures
Stacking sequences of the Crystal structures of (a) 3C SiC, (b) 4H SiC, and (c) 6H SiC.
The term “silicon carbide” is commonly used to describe a range of materials that are in fact quite distinct.
Mechanical engineers may use SILICON CARBIDE to describe ceramics which are fabricated from relatively impure SiC crystallites bonded together with various binders under temperature and/or pressure, while electrical engineers may use the term to describe high purity single crystal wafers of SiC.

APPLICATIONS BASED ON MECHANICAL PROPERTIES
All forms of silicon carbide are well known as hard materials occupying a relative position on Mohs’ scale between alumina at 9 and diamond because of its high thermal conductivity and low thermal expansion, silicon carbide is very resistant to thermal shock as compared to other refractory materials.
Until the recent emergence of silicon carbide as a significant material for electronics, the mechanical properties of SiC-ceramics were the dominant commercial interest.
The formation of SiC powder is an essential pre-requisite to the manufacturing of many types of ceramic articles, which are subsequently obtained by shaping the manufactured silicon carbide powder.
SiC powders with variable purity levels, crystal structures, particle sizes, shapes, and distributions can be prepared via several routes.
Methods that have been examined include: growth by sublimation carbothermic reduction (the Acheson Process), conversion from polymers and gas phase chemical reactions.
Although brittle in nature, silicon carbide ceramics are leading materials for rotating and static components in many mechanical applications.
They are characterized by low fracture toughness and limited strain-to-failure as compared to metals.
The strength of a silicon carbide ceramic component is generally determined by pre-existing flaws introduced into the material during processing.
The type, size, shape, and location of the flaws vary considerably and, consequently, so does the strength.
Silicon carbide ceramics made by different techniques also have quite distinct mechanical properties.
For example, sintered silicon carbide retains SILICON CARBIDEs strength at elevated temperatures and shows excellent time-dependent properties such as creep and slow crack growth resistance.
In contrast, reaction-bonded SiC, because of the presence of free silicon in SILICON CARBIDEs microstructure, exhibits slightly inferior elevated temperature properties.
The extreme hardness of silicon carbide leads to its use as a coating when wear resistance is important, such as brake linings and electrical contacts, and in non-slip applications such as floor or stair treads, terrazzo tile, deck-paint formulations, and road surfaces.
SiC is also commonly used in mechanical seals found in pumps, compressors, and agitators in a wide variety of demanding environments including highly corrosive ones.
Silicon carbide is harder, yet more brittle, than other abrasives such as aluminum oxide.
Because the grains fracture readily and maintain a sharp cutting action, silicon carbide abrasives are usually used for grinding hard, low tensile-strength materials such as chilled iron, marble, and granite, and materials that need sharp cutting action such as fiber, rubber, leather, or copper.
Silicon carbide is also used in a loose form for lapping; mixed with other materials to form abrasive pastes, or used with cloth backings to form abrasive sheets, disks, or belts.

APPLICATIONS BASED ON ELECTRONIC AND OPTICAL PROPERTIES
In recent years, SiC has emerged as a promising material for electronics.
Silicon carbide is considered a wide bandgap material since the electronic bandgaps of the different polytypes range from 2.4eV to 3.3eV (c.f., silicon with a bandgap of 1.1eV).
In some respects, such a wide range of bandgaps is unexpected— particularly when the crystal structures of the polytypes differ only in the stacking sequence of otherwise identical bilayers.
Research in recent years has enabled the development of processing techniques that enable the material properties of silicon carbide to be modified successfully for electronics, in particular power electronics and sensors.
In addition, silicon carbide is commonly used as a substrate material for light emitting diodes where SILICON CARBIDE acts as a foundation on which optically active layers can be grown.
This growth utilizes the close lattice match between 6H SiC, gallium nitride and the high thermal conductivity of SiC to remove the heat generated in the LED.
One application where silicon carbide is making a big impact is gas sensors.
Its wide band gap gives it very low intrinsic carrier concentration, making sensing possible in very hot gases, such as the pollutants released in combustion engines and the sulphurous emissions from volcanic vents.
A typical silicon-carbide gas sensor is about 100 μm across and a fraction of a millimeter thick, and are typically based on a capacitor (MIS structure) with a catalytic contact.
The dielectric layer allows these devices to operate at temperatures in excess of 900°C,14 by separating the metal from the silicon carbide.
In this technology, dielectric layers are typically metal oxide materials such as TiO2, which can be deposited in a variety of manners—including in-situ oxidation of metal layers or more sophisticated techniques such as Atomic Later Deposition with relevant precursors.
When the metal surface is exposed to a gas mixture, SILICON CARBIDE speeds up the breakdown of the gas molecules, releasing ions that modify the electrical properties of the device.
For hydrogen and hydrogen containing molecules, the hydrogen atoms can diffuse easily through thick or dense catalytic contacts to form the charged layer following decomposition of the gas molecule that occurs at temperatures above 150 °C in the sub-millisecond time scale.
The response of the sensor can be measured via a number of methods including: capacitance shift, voltage shift required to maintain capacitance, or the leakage current through the dielectric layers.
The high electrical response speed makes silicon carbide sensors suitable for the detection of gas species in rapidly varying environments, such as close to the manifold region in car exhausts, unlike conventional ceramic based sensors, which have a response time in the region of 10 seconds under these conditions.

Preferred Choice for Demanding Applications
The microstructure and excellent physical properties of 3M™ Silicon Carbide Materials allow it to withstand some of the most demanding conditions in a wide variety of industries. Components made of 3M silicon carbide have an excellent track record over decades of use, and applications for these versatile materials continue to expand. Our experienced scientists work to develop ceramic-based solutions tailored to customers’ requirements.

Durable Under Extreme Conditions
silicon carbide materials offer tribological performance under high load, including pressure, sliding speed and temperature.
Components manufactured from SILICON CARBIDE provide long-lasting service due to SILICON CARBIDEs high resistance to wear, corrosion resistance in aggressive media and thermal shock resistance with low distortion under thermal loads.

The corrosion-resistant grade
Silicon Carbide Grade C 
Resistance to corrosion is a particular problem where aggressive chemicals or hot water are being transferred, e.g. by circulating pumps. 3M silicon carbide grade C has proven highly effective in corrosive environments.

The high-strength grades
Silicon Carbide Grade F plus and Grade T plus 
Two high-density materials achieve the optimum strength for silicon carbide. These non-porous, fine-grained grades are designed to provide very high mechanical strength and edge stability. 3M silicon carbide grade F plus and grade T plus are ideal materials for complex thermal and mechanical loads.

The tribological grades
Silicon Carbide Grade P and Grade G 
These grades offer improved dry run and mixed friction properties that are especially valuable in sliding and friction systems.

Chemical and Physical Properties

Property Name and Property Value
Molecular Weight: 40.096
Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 1
Rotatable Bond Count: 0
Exact Mass: 39.976926534
Monoisotopic Mass: 39.976926534
Topological Polar Surface Area: 0 Ų
Heavy Atom Count: 2
Formal Charge: 0
Complexity: 10
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Coun: 0
Covalently-Bonded Unit Count: 1
Compound Is Canonicalized: Yes

Low density: (3.07 to 3.15 g/cm3)
High hardness: (HV10 ≥ 22 GPa)
High Young’s modulus: (380 to 430 MPa)
High thermal conductivity: (120 to 200 W/mK)
Low coefficient of linear expansion: (3.6 to 4.1x10-6/K at 20 to 400°C)
Maximum operating temperature of SSiC under inert gas: 1,800°C
Excellent thermal shock resistance of SiSiC: ΔT 1,100 K
Erodible
Corrosion and wear resistant even at high temperatures

SiC’s Fascinating Properties
SiC, also known as carborundum, is a combination of silicon and carbide in a crystalline structure, and there are about 250 different crystalline forms in which SiC can be found.
Silicon carbide can take on many different forms: individual grains of SiC can be sintered together to form strong ceramics; fibers of SiC can be added to a polymer matrix to form a composite material, and large, individual crystals of silicone can be grown for use in semiconductor applications.
SiC also appears in nature, although rarely, in the form of the mineral moissanite.

Lightweight and Stable
SiC has an average density on the order of 3 g/cm3, which makes it relatively light in weight.
SILICON CARBIDE is chemically inert and corrosion-resistant, and SILICON CARBIDE is not attacked by any acids, molten salts, or alkalis even when exposed to temperatures up to 800°C.
SiC is an extremely hard and strong material (which makes sense considering SILICON CARBIDEs application as an abrasive material).
SiC has a very low coefficient of thermal expansion, which means that even when exposed to extreme temperature changes, SILICON CARBIDE remains dimensionally stable (e.g., SILICON CARBIDE will not significantly expand when exposed to heat or significantly contract when exposed to cold).
SILICON CARBIDE also has excellent thermal shock resistance.
A Sublime Material
One of the most fascinating properties of silicon carbide is that it is capable of sublimation: when temperatures are sufficiently high enough, SiC skips the liquid form and goes directly to a gaseous form.
This means that SILICON CARBIDE turns into a vapor instead of melting.
The sublimation temperature of silicon carbide (where this solid-to-vapor transition takes place) is around 2700°C (which is around half the surface temperature of the sun).
As a semiconductor material, metallic conductivity can be achieved by heavy doping with nitrogen, aluminum, or boron.
SILICON CARBIDE can be doped n-type by phosphorous or nitrogen and p-type of gallium, aluminum, boron, or beryllium.

The Many Applications of Silicon Carbide
Besides its applications in semiconducting, SiC is also used for SILICON CARBIDEs such as bulletproof vests, ceramic plates, thin filament pyrometry, foundry crucibles, and car clutches. In terms of electrical applications, one of SILICON CARBIDEs earliest uses was as a lightning arrester in a high-voltage power system as engineers and scientists recognized that silicon carbide performs well even in the presence of high voltages and high temperatures. More modern applications of silicon carbide in electronics include Schottky diodes, MOSFETs, and power electronics.
Whether SILICON CARBIDE’s being used as an abrasive polishing material or as the semiconductor for a Schottky diode, SiC is certainly robust and multi-faceted.
Sublimation, extreme chemical inertness and corrosion resistance, excellent thermal properties, and SILICON CARBIDEs ability to be grown as a single-crystal structure are just a few of its outstanding properties.

Physical Description
Silicon carbide appears as yellow to green to bluish-black, iridescent crystals.
Sublimes with decomposition at 2700°C.
Density 3.21 g cm-3. Insoluble in water.
Soluble in molten alkalis (NaOH, KOH) and molten iron.

Color/Form
EXCEEDINGLY HARD, GREEN TO BLUISH-BLACK, IRIDESCENT, SHARP CRYSTALS
HEXAGONAL OR CUBIC
Yellow to green to bluish black, iridescent crystals.

Melting Point
-4892 °F (Sublimes) (NIOSH, 2016)
-2600 °C
-4892°F (sublimes)

The Solar Energy Technologies Office (SETO) supports research and development projects that advance the understanding and use of the semiconductor silicon carbide (SiC).
SiC is used in power electronics devices, like inverters, which deliver energy from photovoltaic (PV) arrays to the electric grid, and other applications, like heat exchangers in concentrating solar power (CSP) plants and electric vehicles.
When PV modules generate electricity, energy first flows through a power electronics device that contains a semiconductor.
Until around 2011, silicon was the preferred semiconductor used to make these devices, but research has shown that SiC can be smaller, faster, tougher, more efficient, and more cost-effective.
SiC withstands higher temperatures and voltages than silicon, making it a more reliable and versatile inverter component.
Inverters convert direct current electricity generated by solar panels from to grid-compatible alternating current.
During the conversion process, some energy is lost as heat.
State-of-the-art silicon inverters operate at 98% efficiency, whereas SiC inverters can operate at about 99% over wide-ranging power levels and can produce optimal quality frequency.
While the 1% increase in efficiency might seem small, SILICON CARBIDE represents a 50% reduction in energy loss.
With 60 gigawatts of solar installed in the United States, a 1% increase in efficiency would amount to 600 megawatts of additional solar power each year and cost savings over the device’s lifetime.

Benefits of Silicon Carbide
SiC has an edge over silicon because SILICON CARBIDE enables the following:
Higher temperatures: SiC-based power electronics devices can theoretically endure temperatures of up to 300° Celsius, while silicon devices are generally limited to 150°C.
Higher voltage: Compared with silicon devices, SiC devices can tolerate nearly 10 times the voltage, take on more current, and move more heat away from the energy system.
Faster switching: A power electronics device needs a switch that turns on to convert low voltage to higher voltage.
SiC can switch on and off quickly, and although some energy is lost during switching, faster switching limits that loss and improves device efficiency.
Less-costly equipment: SiC translates to lower system costs because SILICON CARBIDE allows for smaller, more affordable equipment.
For example, the heat sink, which protects the rest of the components by taking on excess heat, can be smaller because with less energy loss, less heat is produced.

The Wide-Bandgap Advantage
One attribute is responsible for these benefits: SiC’s wide bandgap.
The bandgap is a measure of energy that signifies the distance between two states—an electron’s starting point in the valence band, which is the nonconduction state, and the level it has to move to in order for electricity to flow.
The wide bandgap allows for high voltage, which means SiC can better tolerate voltage spikes, and because devices can be thinner, they perform faster.

Solar and Silicon Carbide Research Directions
Inverters and other power electronics devices are processed on wafers, similar to building integrated circuits on silicon.
And just like silicon, as time has progressed, the wafer sizes have increased, making SILICON CARBIDE process more circuits per batch and lowering cost.
The cost of a 4-inch wafer dropped by half between 2009 and 2012 thanks in part to fabrication improvements and a higher rate of SILICON CARBIDEion.
At the same time, sales of SiC devices more than tripled.
Around 2015, typical wafer size increased to about 6 inches in diameter.
Now researchers are working to expand the use of SiC to the national grid by developing power electronics devices that link distribution lines to transmission lines.
This could potentially do away with huge transformers and save energy.
SiC could save energy in other areas, too, especially in electrification of transportation.
In 2017, SETO launched a funding program to examine some of these issues.
The Advanced Power Electronics Design for Solar Applications awardees have several projects involving silicon carbide:
Flex Power Control, Inc.
North Carolina State University
Oak Ridge National Laboratory
University of Arkansas
University of Texas at Austin
University of Washington

Some of these projects focus on making inverters and converters that last longer, work more efficiently, and reduce costs.
Others are furthering grid integration by designing devices that can connect with energy storage or load-management devices, detect and respond to abnormal current, or rapidly restore power after an outage.
Through this work, SETO aims to develop tools that help grid operators better control solar generation, enable delivery of solar through microgrids, increase grid resiliency, and improve solar reliability for customers.
In addition, three semifinalists in the first round of the American-Made Solar Prize, a competition to revitalize U.S. solar manufacturing, are developing SiC devices: Infineon Technologies America is working on a 1,500-volt converter, BREK Electronics is working on a 250-kilowatt string inverter, and Imagen is working on a three-port high-frequency conversion system.
SiC can also be processed into a ceramic for CSP applications.
Such ceramics move heat well.

Depositor-Supplied Synonyms of SILICON CARBIDE 

Carborundum
409-21-2
Silicon monocarbide
methanidylidynesilanylium
Silicon carbide (SiC)
Silicon carbide whiskers
Silicon carbide powder
MFCD00049531
Carborundeum
Tokawhisker
Betarundum
Carbolon
Nicalon
Silundum
Carbon silicide
Green densic
Betarundum UF
Carbofrax M
Annanox CK
Betarundum ST-S
Silicon carbide, beta-phase
Crystolon 37
Crystolon 39
Betarundum ultrafine
Silicon Carbide Micron Powder
Hitaceram SC 101
SC 9 (Carbide)
Densic C 500
Green densic GC 800
KZ 3M
KZ 5M
KZ 7M
SCW 1
DU-A 3C
CCRIS 7813
DU-A 1
DU-A 2
DU-A 3
DU-A 4
HSDB 681
SC 9
UA 1
UA 2
UA 3
UA 4
SD-GP 6000
SD-GP 8000
UF 15
EINECS 206-991-8
SC 201
UNII-WXQ6E537EW
YE 5626
carbidosilicon
Siliciumcarbid
Siliziumkarbid
GC 10000
Carborundum, CP
Silicon carbide beta
Silicon(IV) carbide
Silicon carbide Alpha
Silicon carbide, alpha
Silicon carbide 1-3um
Silicon Carbide Nanowire
SIC B-HP
silicon carbide whis-kers
[SiC]
Silicon carbide Nonfibrous
Silicon carbide, Fibrous (including whiskers)
EC 206-991-8
Silicon carbide, Nonfibrous
METHANIDYLIDYNESILICON
Nano Silicon Carbide Powder
Silicon Carbide Fine Powder
beta-Silicon carbide 0.5um
WXQ6E537EW
Silicon Carbide Micronwhisker
Silicon Carbide Nanoparticles
Silicon carbide, -100 mesh
Silicon carbide, -325 mesh
DTXSID5052751
Silicon Carbide Submicron Powder
CHEBI:29390
8538AF
Silicon Carbide Nanoparticle Dispersion
92843-12-4
Magnesium Sulfide (MgS) Sputtering Targets
FT-0695130
Silicon carbide (beta), SiC, 97.5% Nano
Silicon carbide, 200-450 mesh particle size
Silicon Carbide (amorphous) Powder, 99+% Nano
Beta-Silicon Carbide SiC GRADE B-hp (H?gan?s)
Q412356
Beta-Silicon Carbide SiC GRADE BF 12 (H?gan?s)
Beta-Silicon Carbide SiC GRADE BF 17 (H?gan?s)
Silicon carbide, nanopowder, <100 nm particle size
Silicon carbide, -400 mesh particle size, >=97.5%
Alpha-Silicon Carbide SiC, min. 99.8% (metal basis)
Silicon Carbide, F 100, green, main particle size 150-106 micron
Silicon Carbide, F 1000, green, main particle size 16-0.2 micron
Silicon Carbide, F 150, green, main partilce size 106-63 micron
Silicon Carbide, F 280, green, main particle size 89-23 micron
Silicon Carbide, F 360, green, main particle size 61-12 micron
Silicon Carbide, F 40, green, main particle size 500-355 micron
Silicon carbide, F 400, green, main particle size 49-8 micron
Silicon Carbide, F 60, green, main particle size 425-180 micron
Silicon Carbide, F 600, green, main particle size 29-2 micron
Silicon Carbide, F 800, green, main particle size 22-1.3 micron
Beta-Silicon Carbide SiC, highest purity min. 99.995% (metal basis)
Silicon Carbide, F 1200, green, main particle size 11,4-0,2 micron
STARCERAM? S, Silicon Carbide, (rtp), Grade HQ (KYOCERA Fineceramics)
STARCERAM? S, Silicon Carbide, (rtp), Grade HQ-F (KYOCERA Fineceramics)
STARCERAM? S, Silicon Carbide, (rtp), Grade RQ (KYOCERA Fineceramics)
STARCERAM? S, Silicon Carbide, (rtp), Grade SQ (KYOCERA Fineceramics)
Silicon carbide sputtering target, 25.4mm (1.0in) dia x 3.18mm (0.125in) thick
Silicon carbide sputtering target, 50.8mm (2.0in) dia x 3.18mm (0.125in) thick
Silicon carbide sputtering target, 50.8mm (2.0in) dia x 6.35mm (0.250in) thick
Silicon carbide sputtering target, 76.2mm (3.0in) dia x 3.18mm (0.125in) thick
Silicon carbide sputtering target, 76.2mm (3.0in) dia x 6.35mm (0.250in) thick
Silicon carbide, nanofiber, D <2.5 mum, L/D >= 20, 98% trace metals basis
STARCERAM? S UF, Silicon Carbide, SiC Grade UF-05 (KYOCERA Fineceramics)
STARCERAM? S UF, Silicon Carbide, SiC Grade UF-10 (KYOCERA Fineceramics)
STARCERAM? S UF, Silicon Carbide, SiC Grade UF-15 (KYOCERA Fineceramics)
STARCERAM? S UF, Silicon Carbide, SiC Grade UF-25 (KYOCERA Fineceramics)