ALGAN GAN HIGH-ELECTRON-MOBILITY FIELD-EFFECT TRANSISTORS WITH LOW 1/F NOISE/

Low-frequency noise in the frequency region of 20 Hz to 20 kHz is inve stigated in AlGaN/GaN high electron mobility transistors (HEMTs) grown on SiC substrates. The noise spectra have the form of the 1/f (flicke r) noise. The measured Hooge parameter is as low as 0.0001. This value is comparable with Hooge parameter values for commercial GaAs field e ffect transistors and approximately two orders of magnitude smaller th an Hooge parameter value measured for AlGaN/GaN heterostructures grown on sapphire. The level of noise depends on the gate leakage current; the noise is much higher in devices with a high gate leakage current, The small measured values of the Hooge parameter are related to a smal ler leakage current and to a better material quality of the devices on SIC substrates and to a high electron sheet density. The low levels o f the 1/f noise in the AlGaN/GaN HEMTs on SIC substrates make them sui table for applications in communication systems, (C) 1998 American Ins titute of Physics. [S0003-6951(98)00934-6]