AlGaN/GaN high electron mobility transistors (HEMTs) were grown by molecular beam epitaxy (MBE) on 2 in. diameter GaN buffer layers grown by hydride vapor epitaxy (HVPE) on sapphire substrates. HEMTs with 1 mum gate length displayed excellent dc and rf performance uniformity with up to 258 separate devices measured for each parameter. The drain-source saturation current was 561 mA with a standard deviation of 1.9% over the 2 in. diameter, with a corresponding transconductance of 118 +/- 3.9 mS/mm. The threshold voltage was -5.3 +/- 0.07 V. The rf performance uniformity was equally good, with an f(T) of 8.6 +/- 0.8 GHz and f(max) of 12.8 +/- 2.5 GHz. The results show the excellent uniformity of the MBE technique for producing AlGaN/GaN HEMTs and also the ability of HVPE to provide high quality buffers at low cost. (C) 2003 Elsevier Ltd. All rights reserved.