Development of AlGaN/GaN/SiC high-electron-mobility transistors for THz detection

Abstract

This paper reports on the AlGaN/GaN Schottky diodes (SDs) and high-electron-mobility transistors (HEMTs) grown on a semi-insulating SiC substrate. The electronic devices demonstrate an improved performance in comparison with the ones processed on a sapphire substrate. Both the SDs and HEMTs show much smaller leakage current density and a higher I_ON/I_OFF ratio, reaching values down to 3.0±1.2 mA/cm² and up to 70 dB under the reverse electric field of 340 kV/cm, respectively. The higher thermal conductivity of the SiC substrate leads to the increase of steady current and transconductance, and better thermal management of the HEMT devices. In addition, a successful detection of terahertz (THz) waves with the AlGaN/GaN HEMT is demonstrated at room temperature. These results open further routes for the optimization of THz designs which may result in development of novel plasmonic THz devices.