Effects of Sulfide Passivation on the Performance of GaAs MISFETs with Photo-CVD Grown P₃N₅ Gate Insulators

Abstract

Accumulation-mode and depletion-mode GaAs metal-insulator-semiconductor field-effect transistors (MISEETs), with sulfur-treatment and a photochemical vapor-deposited- P 3 N 5 gate insulator, have been successfully fabricated. The devices have good linearity, low hysteresis in current-voltage characteristics, and the instability of the current less than 22 percent for the period of 1.0-1.0×10 4 s. The effective electron mobility and extrinsic transconductance of the FETs at room temperature are about 1300 cm 2 /V·s and 1.41 mS/mm for the accumulation-mode, and about 4500 cm 2 /V·s and 4 mS/mm for the depletion-mode, respectively. Capacitance-voltage ( C - V ) characteristics and Auger electron spectroscopy (AES) analysis for different sulfur-treatment conditions are discussed. The atomic concentration ratios of sulfur and oxygen to arsenide on GaAs surfaces and GaAs metal-insulator-semiconductor (MIS) interface properties are critically dependent on sulfur pretreatment conditions, and the optimum sulfur-treatment temperature is determined to be about 40° C. The minimum density of interface trap states for an Al/P 3 N 5 /GaAs MIS diode with the optimized surface treatment is about 4.3×10 10 cm -2 eV -1 .