Thin films of gallium arsenide on low-cost substrates. Quarterly project report No. 1, July 5--October 2, 1976

Technical Report · Mon Nov 01 04:00:00 EST 1976

DOI:https://doi.org/10.2172/7318140· OSTI ID:7318140

Ruth, R. P.; Dapkus, P. D.; Dupuis, R. D.; Johnson, R. E.; Manasevit, H. M.; Moudy, L. A.; Yang, J. J.

The first quarter of work on the contract is summarized. The metallorganic chemical vapor deposition (MO-CVD) technique is being applied to the growth of thin films of GaAs and GaAlAs on inexpensive polycrystalline or amorphous substrate materials (glasses, glass-ceramics, alumina ceramics, and metals) for use in fabrication of large-area low-cost photovoltaic device structures. Trimethylgallium (TMG), arsine (AsH/sub 3/), and trimethylaluminum (TMA) 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 in the range approximately 550-850/sup 0/C, to produce the desired film composition and properties. Ten candidate substrate materials have been selected for further experimental investigation, based on a set of qualification criteria and initial experimental tests. To date, only minor differences have been observed in the properties of undoped polycrystalline GaAs films grown on various candidate substrates-including Corning Codes 0317 and 1723 glasses, polycrystalline alumina ceramics ASM805 and ASM838 (from 3M Company), and Mo sheet-with the exception of films deposited on Kovar-type Fe-Ni-Co alloys. Attack of these alloys by AsH/sub 3/ has been observed at temperatures above 500/sup 0/C, with resulting formation of an interface compound and Ni-rich inclusions in the deposited GaAs films. Films on all of the other substrates have typically had growth characteristics in common, with apparent surface grain sizes in the 2-5 ..mu..m range and high electrical resistivity (greater than or equal to 10/sup 5/ ohm-cm), with no evidence of chemical reaction with the film or the reactants under the conditions of growth employed. Large-grain (10-20 ..mu..m) growth of Ge films on Kovar-type alloy surfaces has also been achieved by GeH/sub 4/ pyrolysis indicating considerable promise for this composite as a substrate for subsequent GaAs film growth.

• Research Organization: Rockwell International Corp., Anaheim, CA (USA). Electronics Research Div.
• OSTI ID: 7318140
• Report Number(s): SAN-1202-76/1
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
ARSENIC COMPOUNDS
ARSENIDES
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
COST
CRYSTAL GROWTH
DEPOSITION
DIRECT ENERGY CONVERTERS
FABRICATION
GALLIUM ARSENIDE SOLAR CELLS
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PNICTIDES
SOLAR CELLS
SUBSTRATES
SURFACE COATING