Enhancement-mode InP n-channel metal-oxide-semiconductor field-effect transistors with atomic-layer-deposited Al2O3 dielectrics

Y Q. Wu, Purdue University
Y Xuan, Purdue University
T Shen, Purdue University
P. D. Ye, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University
Z Cheng, AmberWave Systems Corp
A Lochtefeld, AmberWave Systems Corp

Abstract

Enhancement-mode (E-mode) n-channel InP metal-oxide-semiconductor field-effect transistors (MOSFETs) with 0.75-40 mu m gate length fabricated on a semi-insulating substrate with atomic-layer-deposited (ALD) Al2O3 as gate dielectric are demonstrated. The ALD process on III-V compound semiconductors enables the formation of high-quality gate oxides and unpinning of Fermi level on compound semiconductors. A 0.75 mu m gate length E-mode n-channel MOSFET with an Al2O3 gate oxide thickness of 30 nm shows a gate leakage current less than 10 mu A/mm at the highest gate bias of 8 V, a maximum drain current of 70 mA/mm, and a transconductance of 10 mS/mm. The peak effective mobility is similar to 650 cm(2)/V s and the interface trap density of Al2O3/InP is estimated to be similar to(2-3)x10(12)/cm(2) eV.