Uniformity and high temperature performance of X-band nitride power HEMTs fabricated from 2-inch epitaxy

X-band performance;high temperature D.C. operation and uniformity have been evaluated for 1 mu m gate AlGaN/GaN HEMTs grown by RF atomic nitrogen plasma MBE. Deposition and fabrication were performed on 2-inch (0001) sapphire substrates to determine process uniformity. HEMTs with 300 mu m total gate width and dual gate finger geometry have been fabricated with 650-700 cm(2) V-1 xs mobility. Maximum frequency cut-offs on the order of 8-10 GHz were achieved. D.C. performance at room temperature was >500 mA mm(-1), and external transconductance was > 70 mS mm(-1). The transistors operated at test temperatures of 425 degrees C in air. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.