Low-frequency noise in AlGaN/InGaN/GaN double heterostructure field effect transistors was measured at room and elevated temperatures as function of gate and drain voltages. Both 1/f noise and generation-recombination (g-r) noises were observed. The Hooge parameter, alpha, was estimated to be close to 1 x 10(-3). The activation energy for observed g-r noise was found to be E-a similar to 1.6 eV (the largest reported activation energy for GaN based devices). The measurements also confirmed that the double heterostructure provided superior carrier confinement in 2D channel even at high carrier concentrations. (C) 2003 Elsevier Science Ltd. All rights reserved.