S passivation of GaAs and band bending reduction upon atomic layer deposition of HfO2/Al2O3 nanolaminates

F S. Aguirre-Tostado, Univ Texas Dallas
M Milojevic, Univ Texas Dallas
K J. Choi, Univ Texas Dallas
H C. Kim, Univ Texas Dallas
C L. Hinkle, Univ Texas Dallas
E M. Vogel, Univ Texas Dallas
J Kim, Univ Texas Dallas
T Yang, Purdue University
Xianfan Xu, Birck Nanotechnology Center, School of Materials Engineering, Purdue University
P. D. Ye, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University
R M. Wallace, Univ Texas Dallas

Abstract

A systematic study of the interface engineering and dielectric properties of nanolaminated hafnium aluminate on GaAs is presented. The dielectrics were deposited using atomic layer deposition of alternating cycles of HfO2 and Al2O3 on GaAs substrates. High resolution x-ray photoelectron spectroscopy (XPS) showed differences in space charge amounts at the interface for the two surface treatments [NH4OH or (NH4)(2)S]. In-situ XPS analysis shows that chemical bonding to oxygen across the nanolaminate film is independent of the interface formation conditions. In addition, the GaAs surface treated with (NH4)(2)S shows a decreased band bending and slightly thinner films with respect to NH4OH. (C) 2008 American Institute of Physics.