Low frequency noise and screening effects in AlGaN/GaNHEMTs

Abstract
Low frequency noise has been studied in Al0.15Ga0.85N/GaN high electron mobility transistors grown on sapphire substrates by metal organic vapour phase epitaxy. A strong dependence between the Hooge parameter αH and VGS was found. A Hooge parameter as low as 5 × 10-4 was obtained at VGS = 0 V. Mobility fluctuations produced by changes in the rate of trapping charge at dislocations are suggested to be the dominant 1/f noise mechanism, although screening effects by the channel electrons significantly reduce their effect on the 1/f noise properties.