HIGH-FREQUENCY PERFORMANCE OF SIC HETEROJUNCTION BIPOLAR-TRANSISTORS

A compact heterojunction bipolar transistor (HBT) model was employed to simulate the high frequency and high power performances of SiC-based bipolar transistors. Potential 6H-SiC/3C-SiC heterojunction bipolar transistors (6H/3C-HBT's) at case temperatures of 27-degrees-C (300 K) through 600-degrees-C (873 K) were investigated. The high frequency and high power performance was compared to AlGaAs/GaAs HBT's. As expected, the ohmic contact resistance limits the high frequency performance of the SiC HBT. At the present time, it is only possible to reliably produce 1 x 10(-4) OMEGA - cm2 contact resistances on SiC, so an f(T) of 4.4 GHz and an f(max) of 3.2 GHz are the highest realistic values. However, assuming an incredibly low 1 x 10(-6) OMEGA - cm2 contact resistance for the emitter, base, and collector terminals, an f(T) of 31.1 GHz and an f(max) of 12.7 GHz can be obtained for a 6H/3C-SiC HBT.