Low-frequency noise in SiO2/AlGaN/GaN heterostructures on SiC and sapphire substrates

The low-frequency no ise in GaN-based Metal-Oxide-Semiconductor Heterostructure Field Effect Transistors (MOS-HFETs) and HFETs on sapphire and n-SiC substrates were studied. Hooge parameter at zero gate bias was calculated about 8 x 10(-4) for both types of the devices. The AlGaN/GaN MOS-HFETs exhibited extremely low gate leakage current and much lower noise at both positive and negative gate biases. These features demonstrate the high quality of the SiO2/AlCaN heterointerface and feasibility of this technology for high-power microwave transmitter and high-power, high-temperature switches.