Temperature dependence of current-voltage characteristics of npn-type GaN/InGaN double heterojunction bipolar transistors

We investigated the temperature dependence of the common-emitter current-voltage (I-V) characteristics of npn-type GaN/InGaN double heterojunction bipolar transistors. Although the current gain decreases with increasing measurement temperature, the current gain measured at 300 °C is still as high as 308. The reduction of the current gain with temperature is attributed not only to the hole back-injection current from the base into the emitter but also to the shorter minority carrier diffusion length due to the increase in the carrier concentration of the p-InGaN base.