This paper reports a selective dry-etching technique for GaAs MESFET gate recessing, where a thin AlGaAs etch stop is used to precisely control the recess depth. Selective dry etching was achieved by using a CCl2F2/He gas mixture yielding a selectivity of >600 for GaAs over AlGaAs. A thin (35–50 A) AlxGa, _xAs layer (x = 0.3) was used to control the etch depth. The surface composition of the RIE recessed AlGaAs layers was analyzed by angle resolved XPS and compared to the surface compositions of the wet-chemically recessed samples. The standard deviation of MESFET threshold voltage was as low as 20 mV across a 3-in wafer by using this unique selective dry-etch technique. The MESFET’s show excellent electrical characteristics with transconductance of 150 mS/mm for a 1 X 100 µm gate and breakdown voltages as high as 38 V. The uniformity of the electrical parameters was found to be better than the wet-chemically recessed gate MESFET’s.