High-power characteristics of GaN/InGaN double heterojunction bipolar transistors

High-power characteristics have been investigated for GaN/InGaN double heterojunction bipolar transistors (HBTs) on SiC substrates. A base-collector diode showed a high breakdown voltage exceeding 50 V, which is ascribed to a wide band gap of a GaN collector. The maximum collector current is proportional to the emitter size in the emitter-size ranging from 1.5x10(-5) to 1.4x10(-4) cm(2). The corresponding maximum collector current density is as high as 6.7 kA/cm(2), indicating the high current density characteristics of bipolar transistors. A 50 mumx30 mum device operated up to a collector-emitter voltage of 50 V and a collector current of 80 mA in its common-emitter current-voltage characteristics at room temperature. The corresponding power density is as high as 270 kW/cm(2), showing that nitride HBTs are promising for high-power electronic devices in terms of both the material and the device structure. (C) 2004 American Institute of Physics.