Enhancement-mode Al2O3/InAlN/AlN/GaN metal-insulator-semiconductor high-electron-mobility transistor with enhanced breakdown voltage using fluoride-based plasma treatment

We demonstrate an enhancement-mode (E-mode) Al2O3/InAlN/AlN/GaN metal-insulator-semiconductor high-electron-mobility transistor (MISHEMT) with enhanced breakdown voltage. The threshold voltage V-th shifts from -7.6 to 1.8 V using fluoride-based plasma treatment. The gate leakage current and the buffer leakage current were reduced by the conduction band modulation of negative fluorine charges. The reduction in the buffer leakage current enhanced the breakdown voltage from 80 to 183 V with L-GD = 3 mu m. The fabricated E-mode MISHEMT with a gate length of 1 pm exhibits a respectable drain current of 416 mA/mm and a peak transconductance of 150 mS/mm. (C) 2014 The Japan Society of Applied Physics