1200-V 5.2-mΩ² 4H-SiC BJTs With a High Common-Emitter Current Gain

This letter presents fabrication of a power 4H-SiC bipolar junction transistor (BJT) with a high open-base breakdown voltage BVCEOap 1200 V, a low specific on-resistanceRSP_ONap 5.2 mOmegamiddotcm2, and a high common-emitter current gain beta ap 60. The high gain of the BJT is attributed to reduced surface recombination that has been obtained using passivation by thermal silicon dioxide grown in nitrous oxide (N2O) ambient. Reference BJTs with passivation by conventional dry thermal oxidation show a clearly lower current gain and a more pronounced emitter-size effect. BJTs with junction termination by a guard-ring-assisted junction-termination extension (JTE) show about 400 V higher breakdown voltage compared with BJTs with a conventional JTE.