Microwave and millimeter-wave power generation in silicon carbide avalanche devices

Abstract

Silicon carbide (SiC), due to its thermal and electronic properties, has long been considered an excellent device material for microwave and millimeter-wave power generation. Numerical simulations were performed to study the typical power generating capabilities of SiC impact avalanche transit-time (IMPATT) diodes utilizing the recent experimental data available. Operating characteristics of double-drift IMPATT devices at 10, 35, 60 and 94 GHz are compared. Both pulsed mode and continuous-wave (cw) mode operation are studied. Finally, a comparison among SiC, Si, and GaAs double-drift IMPATT devices is made at various frequencies. It is shown that, for the pulsed mode of operation, SiC double-drift IMPATT devices can produce significantly higher powers than Si and GaAs devices at comparable frequencies. In the cw mode of operation, SiC devices can produce significantly more power than GaAs devices at all frequencies. However, a comparison at 94 GHz indicates that SiC IMPATT diodes in the cw mode of operation produce power levels comparable to Si IMPATT devices. At lower frequencies the performance of SiC diodes operating in the cw mode is expected to be better than the performance of Si devices due to the better thermal conductivity of SiC.