Silicon carbide (SiC) is a IV-IV compound semiconductor used in power semiconductors, especially in power electronics at high voltage, high currents and temperatures. Silicon carbide has a large bandgap, wide bandgap (WBG), of 3.1 electron volts( eV) between the conduction band and valence band, allowing high junction temperatures and voltages.
Silicon carbide has better thermal conductivity than silicon and can be used at temperatures up to 300 °C. The optimum voltage range is between 600 V and 2 kV. In addition, silicon carbide is characterized by a high critical field strength, which is decisive for the thickness of the semiconductor layer and its doping so that a certain junction voltage is achieved. In contrast to silicon, the silicon carbide layer can be thinner, which contributes to a significant reduction of the contact resistance in the switching state and thus to a reduction of the power diss ipation.
Silicon carbide is used in power semiconductors in field-effect transistors( FET), junction field-effect transistors( JFET), super junction transistors( SJT), Schottky diodes and IGBTs. Silicon carbide can be used to produce SJT transistors for voltages of over 10 kV, at currents of 10 A and operating temperatures of up to 300 °C, among others. Silicon carbide can, for example, increase the efficiency ofinverters inphotovoltaic systems by over 50%. In addition, the frequency can be increased by a factor of 4 and higher, thus significantly reducing the size, especially since the assembly can be operated at much higher temperatures.