Characteristics analysis of gate dielectrics in AlGaN/GaN MIS-HEMT

Compared with the conventional high electron mobility transistor (HEMT), the metal-insulator-semiconductor (MIS)-HEMT has several advantages such as lower gate leakage current, higher maximum saturation drain current and the better restrain of current collapse. This paper studied the effects of temperature and the thickness of dielectric on the characteristics of Al₂O₃ MIS-HEMT. The device characteristics degrade with the increase of temperature. The thicker dielectric can decrease the gate leakage current. However, it can not provide larger transconductance because the permittivity of Al₂O₃ isn´t very high. Several promising alternatives of gate dielectrics (HfSiON, HfAlON, LT-GaN) are presented in this paper.