An enhancement-mode pseudomorphic high-electron-mobility transistor (E-PHEMT) using a citric acid/hydrogen peroxide etching solution for gate recession is developed. The etch selectivity between GaAs and Al0.2Ga0.8As is more than 165 at 22 degrees C, while the maximum transconductance for the fabricated device with the gate dimension of 160 x 0.25 mu m(2) reaches 502 mS/mm at V-ds =2.7 V. Furthermore, at 12 GHz, the I dB compression output power and gain can reach 13.2 dB m and 17.9 dB, respectively. Operating at 12 GHz, the minimum noise figure at the bias conditions of V-ds=2 V and I-ds= 11 mA decreases to 0.45 dB with the associated gain of 12.95 dB, which is comparable to, or even better than that of, reported low-noise depletion- or enhancement-mode PHEMT devices. The standard deviation of the pinch-off voltage for the E-PHEMT across a 4 in. diameter wafer could be as low as 50 mV. (c) 2007 American Vacuum Society.