AlGaN/GaN high electron mobility transistors (HEMTs) were fabricated on structures grown by hydride vapor phase epitaxy (HVPE). A current gain cut-off frequency, f(t), of 11.5 GHz and a maximum frequency of oscillation, f(max), of 20.5 GHz were achieved for a 1 x 100 mum(2) device at a gate voltage of 0 V and drain voltage of 2 V. This rf performance is comparable to that obtained with MBE- or MOCVD-grown AlGaN/GaN HEMTs of the same dimension and indicates that HVPE can be competitive with these other growth methods for producing high speed nitride-based HEMTs. (C) 2003 Elsevier Ltd. All rights reserved.