Schottky Source/Drain Al2O3/InAlN/GaN MIS-HEMT with Steep Sub-threshold Swing and High ON/OFF Current Ratio

Abstract

Al2O3/InAlN/GaN MISHEMTs with Schottky source and drain were experimentally demonstrated with steep subthreshold swing (SS) at room temperature as well as high temperature up to 150 degrees C. The mechanism for the steep SS was proposed to be based on the dynamic discharging process of the interface states at the Al2O3/InAlN interface and the resultant positive feedback in the turn-on of the drain current. The model was validated by temperature-dependent characterization. The use of the Schottky source/drain contacts can effectively prevent the off-state leakage current, leading to high ON/OFF current ratio of similar to 10(10) in the proposed devices. At room temperature, SS as low as 6.6 mV/dec was observed and SS lower than 60 mV/dec was obtained over a wide drain bias range of 3 similar to 10 V during the forward sweep of V-GS. The proposed device delivers a maximum drain current density of 416 mA/mm and peak extrinsic transconductance of 113 mS/mm