High-temperature characteristics up to 590 °C of a pnp AlGaN/GaN heterojunction bipolar transistor

We investigated the temperature dependence of the common-emitter I-V characteristics of a pnp AlGaN/GaN heterojunction bipolar transistor (HBT) at temperatures ranging from RT to 590 °C. The HBT operated at 590 °C in air with a current gain of 3. Even at 590 °C, the collector-emitter leakage current was as low as 9 μA at the collector-emitter voltage of 40 V. Although there is no significant degradation of the HBT characteristics only by annealing in air at 400 °C for 2 h, the current gain reduced to 30% of the initial one after the common-emitter operation at 400 °C for 2 h.