Silicon Carbide Structure

Silicon carbide (SiC) is a synthetically produced, highly resistant crystalline compound consisting of silicon and carbon that comes in various physical and chemical forms – making it suitable for many different industrial uses.

SiC exists in various crystal structures called polytypes, each distinguished by the stacking sequence of silicon and carbon atoms. Each polytype possesses its own set of electrical and physical characteristics.

Physical

Silicon carbide is an extremely hard material with a Mohs scale rating of 9. Its characteristics include outstanding strength, high thermal conductivity and thermal expansion rates that remain relatively constant, resistance to chemical reaction as well as being impervious to impacts and corrosion.

SiC is composed of covalently bonded tetrahedral units organized into a crystal lattice structure. It crystallizes in close packed structures and typically appears colorless; however, impurities may alter this to yellow, green or bluish-black hues. SiC exists in approximately 250 crystal forms.

SiC is an extremely wide bandgap semiconductor used for various applications in power electronics, from switches and transistors to applications that use less space for greater power output. As its breakdown voltage can withstand higher levels, allowing smaller and faster switching transistors that provide more energy output in less space.

These high-voltage devices make use of its low turn-on resistance and superior switching characteristics as well as its lower threshold temperature for operation.

Silicon Carbide, commonly referred to by its chemical formula of SiC, can be found naturally as moissanite (Moissanite jewels), but all commercially sold SiC has been synthetically produced since 1891 – though small amounts may still exist naturally in certain types of meteorites, corundum deposits, or kimberlites. Most silicon carbide production takes place via physical vapor transport and chemical vapor deposition techniques.

Chemical

Silicon carbide (SiC) is a hard chemical compound made up of silicon and carbon that naturally occurs in extremely small amounts in moissanite, though since 1893 has been mass produced as powder and crystal for use as an abrasive. SiC can also be bonded together into hard ceramics used for car brakes or bulletproof vests; additionally it makes an effective refractory material due to its high melting point and thermal conductivity; its low thermal expansion/stiffendness makes it more resistant against oxidation/abrasion than many other materials out there.

SiC exhibits semiconductor properties when doped with certain substances and, when modified to behave as either an N- or P-type semiconductor. Furthermore, its wide bandgap allows electronics fabricated with SiC to operate at higher temperatures and voltages than silicon electronics – making it suitable for high-power applications.

SiC is a material composed of silicon and carbon held together by strong covalent bonds in an extremely close-packed crystal lattice, creating polytypes of material with distinctive arrangements of silicon and carbon atoms, held in close-packed positions within its crystal lattice structure. Different arrangements create different polytypes; diamond structure (referred to as /3-SiC) is most prevalent but hexagonal and rhombic stacking can also occur. All forms exhibit extremely tough properties with Mohs hardness ratings of 9.0-10.6, comparable with hardness values similar to diamond at 10 while harder than both alumina (9), quartz (7+).

Electrical

Silicon carbide in its pure form is an electrical insulator. However, with the addition of controlled impurities (known as dopants), silicon carbide can be transformed into an electronic semiconductor material. Doping with aluminum, gallium and boron creates a P-type semiconductor; nitrogen and phosphorus doping results in an N-type semiconductor.

SiC is an ultra-durable hexagonal structure chemical compound made by bonding silicon with carbon through strong covalent bonds to form strong band-gap semiconductor properties, offering low electron freeing energies than silicon or other traditional semiconductor materials – making it perfect for high temperature applications such as high pressure plasma applications.

Silicon carbide’s multilayered crystal structure lends itself to numerous polytypes. Each polytype differs in its crystal structure due to the unique stacking sequence between silicon and carbon bilayers; examples of such structures include cubic, rhombohedral and hexagonal.

Rhombohedral and cubic polytypes are widely utilized for electronics applications due to their higher saturation electron velocity which increases switching speed and performance of transistors. Recently however, hexagonal polytypes have gained attention as an excellent power handling material as their low concentration of charge carriers at room temperature allows a greater electrical load before thermally liberated electrons flood the semiconductor and lock it into an “on” state.

Mechanical

Silicon carbide (SiC) is one of the hardest known materials. With a Mohs hardness rating of 9, it sits comfortably between boron carbide at 9.5 and diamond at 10. SiC is an exceptionally hard ceramic material with exceptional resistance to corrosion, high temperatures and thermal shock; additionally it boasts zero porosity for zero distortion dimensional stability; chemically aggressive media can withstand its heat without harming SiC while making it an excellent material choice for gas sealing rings and mechanical seals.

SiC’s high density and stiffness makes it an excellent abrasive material for grinding, honing, water-jet cutting and sandblasting applications. In addition, SiC glazes are often applied to ceramics and stoneware glazes in order to increase firing temperatures, reduce cracking rates and improve abrasion resistance; SiC powder may even be included into glazes made for alumina and zirconia in order to increase strength and hardening characteristics.

SiC is also an ideal material for modern lapidary due to its uniformity and abrasion resistance, as well as being heat and pressure resistant – qualities which make it the ideal material for use in lining work within kilns, where gas emissions could lead to cracking glaze.

SiC boasts an extremely wide band-gap compared to silicon, making it suitable for high-power applications at higher frequencies and voltages. Tensile tests of single NWs with differing ODD structural occupation ratios show that ODD regions have a strong saddle-shaped effect on mechanical properties enhancing tensile strengths and elastic strains of these NWs.