Microwave performance of recessed gate Al0.2Ga0.8N/GaN HFETs fabricated using a photoelectrochemical etching technique

Abstract

This is the first report on the fabrication of AlGaN/GaN HFETs which has a recessed gate structure achieved by the photoelectrochemical etching technique. Optimal photoelectrochemical wet etching conditions were stabilized and applied for the device fabrication. The DC and large-signal RF performance of thus fabricated device is presented as well. The ohmic contacts fabricated on the n(+)-GaN layer exhibited contact resistivity of mid 10(-6) Omega cm(2) and resulted in a linear I-V characteristics during an operation of device. The maximum drain-source current density is approximately 174 mA mm(-1) (at V-GS = 1 V), and the transconductance of approximately 68 mS mm(-1) (at V-GS = -1.1 V, V-DS = 6 V). The maximum frequency is measured to be approximately 31 GHz, and an RF power of 84 mW mm(-1) at 1.8 GHz for a 1400-mum wide gate device. (C) 2002 Elsevier Science B.V. All rights reserved.