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Title: Preparation of gallium nitride surfaces for atomic layer deposition of aluminum oxide

A combined wet and dry cleaning process for GaN(0001) has been investigated with XPS and DFT-MD modeling to determine the molecular-level mechanisms for cleaning and the subsequent nucleation of gate oxide atomic layer deposition (ALD). In situ XPS studies show that for the wet sulfur treatment on GaN(0001), sulfur desorbs at room temperature in vacuum prior to gate oxide deposition. Angle resolved depth profiling XPS post-ALD deposition shows that the a-Al{sub 2}O{sub 3} gate oxide bonds directly to the GaN substrate leaving both the gallium surface atoms and the oxide interfacial atoms with XPS chemical shifts consistent with bulk-like charge. These results are in agreement with DFT calculations that predict the oxide/GaN(0001) interface will have bulk-like charges and a low density of band gap states. This passivation is consistent with the oxide restoring the surface gallium atoms to tetrahedral bonding by eliminating the gallium empty dangling bonds on bulk terminated GaN(0001)
Authors:
 [1] ;  [2] ; ; ;  [3] ; ; ;  [1] ; ;  [4]
  1. Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)
  2. (United States)
  3. Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093 (United States)
  4. Department of Nanoscale Science and Engineering, University at Albany–State University of New York, Albany, New York 12222 (United States)
Publication Date:
OSTI Identifier:
22308385
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 10; Other Information: (c) 2014 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; ALUMINIUM OXIDES; ATOMS; CHEMICAL SHIFT; DENSITY; DEPOSITION; GALLIUM; GALLIUM NITRIDES; NUCLEATION; SIMULATION; SUBSTRATES; SURFACES; X-RAY PHOTOELECTRON SPECTROSCOPY