Silicon Carbide Drives a Revolution in Power Electronics

SiC has an expansive bandgap that enables power systems to operate at higher temperatures, voltages and frequencies without incurring additional BOM costs, leading to lower costs overall and more efficient and smaller devices.

Silicon carbide was, until 1929 when boron carbide was developed, the toughest known synthetic material with a Mohs hardness rating of 9, and could even compare closely with diamond.

Physical Properties

Silicon carbide’s remarkable physical and electrical properties are sparking an unprecedented revolution in power electronics. A wide bandgap semiconductor, it provides opportunities for smaller, faster and more reliable electronics that can handle higher temperatures, voltages and frequencies than their silicon counterparts.

Solar systems rely heavily on reflectivity to achieve their high longevity, which they require in order to operate continuously for years at a time. Reflectivity also finds use as structural materials in bulletproof vests and composite armor as well as automotive parts (brake disks), lightning arresters, abrasives and observatories mirror materials.

Silicon carbide first discovered as the moissanite mineral in 1893 during the Canyon Diablo meteorite explosion in Arizona was first synthesized on a small scale by Edward Goodrich Acheson in 1891 and later by Henri Moissan using various techniques. Today it’s produced by melting silica sand with carbon sources, like coal, in granite crucibles at high temperature until crystals form that can then deposit on graphite rods at lower temperatures to produce pure silicon carbide which remains colorless but brown or black industrial versions contain iron impurities while it can also be doped with nitrogen or phosphorus to create an n-type semiconductor or aluminum, boron or gallium for p-type semiconductor properties.

Chemical Properties

Silicon Carbide (SiC), has been produced synthetically since the late 19th century, and widely utilized as an abrasive material in sandpaper and grinding wheels. Recently however, SiC has seen renewed use as an essential technological material due to its extraordinary thermal and electrical properties.

SiC, composed of silicon and carbon atoms bonded in an hexagonal crystal lattice, offers strong physical characteristics: low thermal expansion, resistance to thermal shock and wide band-gap semiconductor properties that enable electrons to move more easily between its atoms than with silicon, making it a superior material for electronic applications.

SiC is insoluble in water and alcohol, while being soluble in fused alkalies and molten salts; its resistance to oxidation at high temperatures makes it noncombustible and toxic fume-free; however, long-term exposure may result in progressive pulmonary enlargement causing progressive fibrosis of lungs resulting in progressive pulmonary fibrosis resulting in progressive lung enlargement; it has been listed by IARC as possible human carcinogen.

Mechanical Properties

Silicon carbide is one of the lightest and hardest materials ever known. It withstands abrasion, erosion and corrosion for optimal use in chemical plants, mills, expanders and nozzles.

This material is exceptionally hard, stiff, low thermal expansion and retains strength at temperatures as high as 1,400degC. In addition, it stands out among advanced ceramic materials for being highly resistant to acids and alkalis.

Current applications of sic silicon carbide for power electronics use range widely and it helps accelerate decarbonization by improving electric motor efficiency, thus increasing driving distances while simultaneously decreasing size and weight of battery management systems. Sic silicon carbide also offers exceptional quality, reliability, and efficiency that makes its use an appealing alternative to metals like nickel.

Electrical Properties

Silicon carbide has found widespread application in power electronics applications and as a replacement for traditional silicon devices due to its fast switching times and higher blocking voltage capabilities, along with its wide bandgap that enables electronic circuits to run more quickly at higher temperatures while remaining more reliable than their silicon counterparts.

Electrical properties of sic silicon carbide can be altered by doping it with impurities. Dopants typically fill vacant lattice sites within its pristine crystal structure; their activation energies vary according to polytype.

As a result of its unique atomic arrangement between silicon and carbon atoms in its crystal structure, each polytype of SiC demonstrates distinct semiconductor characteristics. As shown by the following table containing some of the main electrical properties for 3C, 4H, and 6H SiC at room temperature; these depend strongly on crystallographic current flow direction as well as applied electric fields (i.e. nonisotropic).

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