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Title: The chemistry of sulfur passivation of GaAs surfaces

Journal Article · · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA)
DOI:https://doi.org/10.1116/1.576822· OSTI ID:6783199
; ;  [1];  [2]
  1. Optoelectronic Computing Systems Center, Colorado State University, Fort Collins, CO (USA) Department of Electrical Engineering, Colorado State University, Fort Collins, CO (USA)
  2. Lawrence Berkeley Laboratory, Berkeley, CA (USA)

Recently, sulfur treatments have been reported which electrically passivate the GaAs and InP surfaces. Since then, a variety of analytical techniques have been applied in an attempt to explain these observations. In particular x-ray photoelectron spectroscopy (XPS) has been used to determine the S--GaAs bonding. These experiments have not fully explained the surface chemistry since a number of different bonding configurations have been reported. This paper reports the results of our XPS and Auger analysis of Na{sub 2}S{center dot}9H{sub 2}O, (NH{sub 4}){sub 2}S, and H{sub 2}S treated GaAs surfaces. We propose a model which includes a kinetic barrier to S--GaAs chemical bonding. In the absence of an excitation source and/or surface defects, the S only physisorbs on the surface. With an excitation and/or defects the S chemisorbs on the surface and causes shifted core level peaks to appear in the XPS spectra.

OSTI ID:
6783199
Journal Information:
Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA), Vol. 8:3; ISSN 0734-2101
Country of Publication:
United States
Language:
English