Postprocessing annealing effects on direct current and microwave performance of AlGaN∕GaN high electron mobility transistors

Abstract

The effects of postprocessing annealing on direct current, radio frequency small signal, and power performances of AlGaN∕GaN high electron mobility transistors with a gate-length of 0.2μm were investigated. The postannealing technique can improve the device performance, especially, after 10min postannealing at 400°C, the gate-to-drain breakdown voltage of devices exhibits remarkable improvement from 25 to 187V. The maximum extrinsic transconductance increases from 223 to 233mS∕mm at a drain bias of 10V after 10min annealing at 400°C. The maximum drain current at a gate bias of 1V increases from 823 to 956mA∕mm. After annealing, the values of the unity current gain cut-off frequency and the maximum oscillation frequency increases from 24 and 80GHz to 55 and 150GHz, respectively. The output power and gain at 10GHz were improved from 16.4dBm and 11.4dB to 25.9dBm and 19dB, respectively.