Interface studies of GaAs metal-oxide-semiconductor structures using atomic-layer-deposited HfO2/Al2O3 nanolaminate gate dielectric

T Yang, Purdue University
Y Xuan, Purdue University
Dmitry Zemlyanov, Purdue University
T Shen, Purdue University
Y Q. Wu, Purdue University
Jerry M. Woodall, Birck Nanotechnology Center, Purdue University
P. D. Ye, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University
F S. Aguirre-Tostado, Materials Science and Engineering, University of Texas at Dallas
M Milojevic, Materials Science and Engineering, University of Texas at Dallas
S McDonnell, Materials Science and Engineering, University of Texas at Dallas
R M. Wallace, Materials Science and Engineering, University of Texas at Dallas

Abstract

A systematic capacitance-voltage study has been performed on GaAs metal-oxide-semiconductor (MOS) structures with atomic-layer-deposited HfO2/Al2O3 nanolaminates as gate dielectrics. A HfO2/Al2O3 nanolaminate gate dielectric improves the GaAs MOS characteristics such as dielectric constant, breakdown voltage, and frequency dispersion. A possible origin for the widely observed larger frequency dispersion on n-type GaAs than p-type GaAs is discussed. Further experiments show that the observed hysteresis is mainly from the mobile changes and traps induced by HfO2 in bulk oxide instead of those at oxide/GaAs interface.