GaN/InGaN heterojunction bipolar transistors with ultra-high d.c. power density (>3MW/cm 2)

Abstract

We report ultra-high-power performance on npn GaN/InGaN double heterojunction bipolar transistors (DHBTs) that is directly grown on a free-standing (FS) GaN substrate. Measured common-emitter current gain (h fe) reaches 80. A quasi-static I-V measurement shows that J C>141kA/cm 2 and a power density of 3.05MW/cm 2 can be achieved for DHBTs grown on an FS-GaN substrate. When the temperature is increased to 250°C, a GaN/InGaN DHBT shows h fe=43 and the offset voltage is reduced from 0.8V at the room temperature to 0.3V. Similarly, the knee voltage is reduced from 5.2V at room temperature to 2.75V at 250°C. In this particular device, breakdown voltage (BV CEO) increases from 90V at room temperature to 157V at 250°C. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.