Temperature Dependence of High-Frequency Performances of AlGaN/GaN HEMTs

Abstract

High-frequency measurements of AlGaN/GaN HEMTs (high electron mobility transistors) with 1.3 μm long gate have been performed at temperatures between 23 and 187 °C. The cut-off frequency fT decreased monotonically with increasing temperature. It was 13.7 and 8.7 GHz at 23 and 187 °C, respectively. The effective electron velocities veff in the channel, evaluated from the relation of total delay time versus the ID-inverse, were 1.2 × 107 and 0.8 × 107 cm/s at 23 and 187 °C, respectively. It has been shown that the present device is in an intermediate state between mobility-dominant and peak-velocity-dominant operations.