High‐performance GaN/InGaN double heterojunction bipolar transistors with power density >240 kW/cm2

Abstract

AbstractWe report GaN/In0.03Ga0.97N npn double heterojunction bipolar transistors (DHBTs) grown on sapphire substrates for high power applications. High current gain and high power density are obtained using a simple single‐growth mesa etching process. A device with an emitter area (AE) of 20×20 µm2 achieves a peak d.c. current gain (β) of 84, a maximum collector current density (JC) of 7.2 kA/cm2 and a maximum power density > 240 kW/cm2. A large‐area (AE = 12163 μm2) multi‐finger device also shows a peak β = 30, maximum collector current (Ic) = 200 mA and maximum d.c. power = 3.76 W. These values are among the best for the reported III‐N HBTs to date (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)