Thin films of gallium arsenide on low-cost substrates. Quarterly technical progress report No. 6 and topical report No. 2, January 1, 1978-April 1, 1978
Year: 1978
Type: report
Abstract: The metalorganic chemical vapor deposition (MO-CVD) technique has been applied to the growth of thin films of GaAs and GaAlAs on inexpensive polycrystalline or amorphous substrate materials (primarily glasses and metals) for use in fabrication of large-area low-cost photovoltaic device structures. Trimethylgallium (TMG), arsine (AsH/sub 3/), and trimethylaluminum (TMAl) are mixed in appropriate concentrations at room temperature in the gaseous state and pyrolyzed at the substrate, which is heated in a vertical reactor chamber to temperatures of 725 to 750/sup 0/C, to produce the desired film composition and properties. The substrate materials used for experimental studies during the quarter included several grades of graphite (from two different manufacturers), commercial-grade Al alloy sheet, large-grained annealed Mo sheet, sputtered Mo films on Corning Code 0317 glass, uncoated 0317 glass, large-grained polycrystalline alumina (Coors Vistal 5), and large-grained bulk polycrystalline GaAs. Results indicted graphite to be a suitable substrate for GaAs film growth by MO-CVD, although some adherence problems were uncountered with improperly prepared graphite surfaces. No major differences were observed for GaAs growth on the various graphites; films approx. 10 ..mu..m thick exhibited apparent grain sizes (indicated by dimensions of surface features) in the 2 to 5 ..mu..m range. Annealed Mo sheet substrate having relatively large grain structure did not appear to produce correspondingly large grains in deposited polycrystalline GaAs films. Results are reported in detail. (WHK)
DOI: 10.2172/5324249
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W41286073