Low frequency noise and screening effects in AlGaN/GaN HEMTs

Low frequency noise has been studied in Al(0.15)G(0.85)N/GaN high electron mobility transistors grown on sapphire substrates by metal organic vapour p hase epitaxy. A strong dependence between the Hooge parameter alpha(H) and V-GS was found. A Hooge parameter as low as 5 x 10(-4) was obtained at V-GS = 0V. Mobility fluctuations produced by changes in the rate of trapping ch arge at dislocations are suggested to be the dominant 1/f noise mechanism, although screening effects by the channel electrons significantly reduce th eir effect on the 1/f noise properties.