Silicon Carbide (SiC): The Wide-Bandgap Semiconductor for Power Electronics

Silicon carbide (SiC) is a compound of silicon and carbon and one of the leading "third-generation" wide-bandgap semiconductors. It exists in roughly 250 crystalline forms called polytypes; the technologically important ones are 3C (cubic, also called beta-SiC, ~2.36 eV bandgap), 6H (hexagonal alpha-SiC, ~3.05 eV), and 4H (hexagonal, ~3.23 eV), the polytype most used for power devices. Its wide bandgap (roughly three times silicon's ~1.1 eV) is what makes it valuable: devices can operate at much higher temperatures and block far higher voltages before breaking down. SiC also has very high thermal conductivity (around 320-350 W/m/K), so it sheds heat efficiently, and a breakdown field roughly an order of magnitude higher than silicon. These properties make SiC the dominant choice for high-power switching: Schottky diodes, JFETs, and especially MOSFETs for EV inverters, solar inverters, and industrial drives. The Tesla Model 3 (2018) was the first electric vehicle to use SiC MOSFETs in its main traction inverter, with each switching position built from multiple 650 V SiC MOSFETs supplied by STMicroelectronics; this catalyzed rapid growth of the SiC industry. Compared with Gallium Nitride (GaN): The Wide-Bandgap Semiconductor Behind Blue LEDs and Fast Chargers, SiC tends to win at higher voltages and currents while GaN excels at high frequency. Manufacturing remains harder than for silicon: producing low-defect crystals (edge, screw, and basal-plane dislocations) is difficult, and the SiC/silicon-dioxide interface inside MOSFETs introduces traps that degrade performance. SiC occurs naturally only as the extremely rare mineral moissanite, first identified in a meteorite by Henri Moissan in 1893; almost all SiC used today is synthetic. See No Single Successor to Silicon: The Heterogeneous Future of Chip Materials for how it fits among silicon alternatives.