Passivated 0.15-mum pseudomorphic high electron mobility transistors are fabricated by combining a wide head T-shaped gate using a dose split method of electron beam lithography and a highly selective and uniform inductively coupled plasma (ICP) recess process. The good DC uniformity was obtained across 4-inch wafer and the uniformity of maximum extrinsic transconductance and threshold voltage are 1.3 and 2.9%, respectively. The obtained uniform device characteristics are attributed to the gate recess etch process with the uniformity less than 5% by the ICP gate recess process. The maximum extrinsic transconductance was 568 mS mm(-1). The cut-off frequency and maximum oscillation frequency were 90 and 160 GHz, respectively. The noise figure minimum measured at 28 GHz was 0.93 dB with associated gain of 10.03 dB. At 40 GHz, F-min is 1.3 dB with G(a) of 8.33 dB. (C) 2003 Elsevier Science B.V. All rights reserved.