Band offsets of atomic-layer-deposited Al2O3 on GaAs and the effects of surface treatment

N V. Nguyen, Natl Inst Stand & Technol, Div Semicond Elect
Oleg A. Kirillov, Natl Inst Stand & Technol, Div Semicond Elect
W Jiang, Natl Inst Stand & Technol, Div Semicond Elect
Wenyong Wang, Natl Inst Stand & Technol, Div Semicond Elect
John S. Suehle, Natl Inst Stand & Technol, Div Semicond Elect
P. D. Ye, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University
Y Xuan, Intel Corp, Santa Clara
N Goel, Intel Corp, Santa Clara
K W. Choi, Intel Corp, Santa Clara
Wilman Tsai, Intel Corp, Santa Clara
S Sayan, Intel Corp, Santa Clara,

Abstract

The metal gate/high-k dielectric/III-V semiconductor band alignment is one of the most technologically important parameters. We report the band offsets of the Al/Al2O3/GaAs structure and the effect of GaAs surface treatment. The energy barrier at the Al2O3 and sulfur-passivated GaAs interface is found to be 3.0 +/- 0.1 eV whereas for the unpassivated or NH4OH-treated GaAs is 3.6 eV. At the Al/Al2O3 interface, all samples yield the same barrier height of 2.9 +/- 0.2 eV. With a band gap of 6.4 +/- 0.05 eV for Al2O3, the band alignments at both Al2O3 interfaces are established. (C) 2008 American Institute of Physics.