High current gain of 3000 for GaN/InGaN HBTs with a regrown base layer

摘要

GaN/InGaN double heterojunction bipolar transistors with the regrown p-InGaN extrinsic base have been fabricated on SiC substrates. The maximum cornmon-emitter current gain exceeds 3000 at the collector current of 20 mA for the 50 μm × 30 μm device. Furthermore, the offset voltage in the common-emitter current-voltage characteristics has reduced from 5 V to 1 V. This result indicates that the large offset voltage reported previously is mainly ascribed to the degraded base ohmic characteristics. The regrowth of p-InGaN is effective to improve the characteristics of nitride heterojunction bipolar transistors.