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Title: Dual passivation of GaAs (110) surfaces using O{sub 2}/H{sub 2}O and trimethylaluminum

The nucleation and passivation of oxide deposition was studied on defect-free GaAs (110) surfaces to understand passivation of surfaces containing only III-V heterobonds. The passivation process on GaAs (110) was studied at the atomic level using scanning tunneling microscopy while the electronic structure was determined by scanning tunneling spectroscopy (STS). The bonding of the oxidant and reductant were modeled with density functional theory. To avoid Fermi level pinning during gate oxide atomic layer deposition, a dual passivation procedure was required using both a reductant, trimethylaluminum (TMA), and an oxidant, O{sub 2} or H{sub 2}O. Dosing GaAs (110) with TMA resulted in the formation of an ordered complete monolayer of dimethylaluminum which passivates the group V dangling bonds but also forms metal-metal bonds with conduction band edge states. These edge states were suppressed by dosing the surface with oxidants O{sub 2} or H{sub 2}O which selectively react with group III-aluminum bonds. The presence of an ordered Al monolayer with a high nucleation density was indirectly confirmed by XPS and STS.
Authors:
;  [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093 (United States)
  2. Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093 (United States)
  3. Department of Physics, Texas State University, San Marcos, Texas 78666 (United States)
  4. (United States)
Publication Date:
OSTI Identifier:
22220208
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 24; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; ALUMINIUM; DENSITY; DENSITY FUNCTIONAL METHOD; DEPOSITION; ELECTRONIC STRUCTURE; FERMI LEVEL; GALLIUM ARSENIDES; OXIDES; PASSIVATION; SCANNING TUNNELING MICROSCOPY; SEMICONDUCTOR MATERIALS; SURFACES; TUNNEL EFFECT; X-RAY PHOTOELECTRON SPECTROSCOPY