Investigation of normally-OFF AlGaN/GaN MIS-HEMTs with Al2O3/ZrOx/Al2O3 charge trapping layer

Abstract

In this paper, normally-OFF AlGaN/GaN high electron mobility transistors (MIS-HEMTs) with partially recessed gate and Al2O3/ZrOx/Al2O3 charge trapping layer gate dielectrics (CTL) are studied. The threshold voltage (Vth) of the proposed CTL-HEMTs is 1.56 V, the sub-threshold slope (S.S) is 90 mV/dec and ION/IOFF ratio is 10⁸. Moreover, saturation drain current (IDmax) and low on-resistance (RON) of CTL-HEMTs is 732 mA/mm and 7.9 Ω•mm (LGS = 3μm). Furthermore, the Bi-direction C-V measurement of the MIS-capacitors was measured to explore the charge trapping behavior. The experimental results prove the potential of ZrOx CTL to realize the normally-OFF operation MIS-HEMTs with desired performance.