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Author Ingerly, D. B. ♦ Swenson, D. ♦ Jan, C. ♦ Chang, Y. A.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ GALLIUM ♦ PHASE DIAGRAMS ♦ NICKEL ♦ ARSENIC ♦ TERNARY ALLOY SYSTEMS ♦ ISOTHERMS ♦ ELECTRIC CONTACTS ♦ SUPERLATTICES ♦ EUTECTICS ♦ INTEGRATED CIRCUITS ♦ METALLIZATION
Abstract Phase equilibria were investigated in the Ga{endash}Ni{endash}As ternary system, with particular emphasis on the regions of technological importance to Ni/GaAs electrical contacts. A 600{degree}C Gibbs isotherm was constructed using x-ray-diffraction analysis and electron probe microanalysis of annealed samples. Additionally, three isopleths (NiAs{endash}GaAs, NiGa{endash}NiAs, and NiGa{endash}GaAs) and a partial liquidus projection were established using differential thermal analysis and metallography. These data were utilized to clarify some discrepancies in the literature pertaining to the constitution of the Ga{endash}Ni{endash}As system, particularly questions about the existence of ternary phases. It was demonstrated that at 600{degree}C, previously reported ternary phases were actually specific compositions of the binary phase, NiAs, which exhibits significant ternary solubility. Additional x-ray-diffraction and differential thermal analysis experiments suggested that superlattice structures based on the NiAs structure may become stable at lower temperatures. A ternary eutectic reaction was shown to occur at 810{plus_minus}5{degree}C, with eutectic point at the composition Ni{sub 0.48}Ga{sub 0.30}As{sub 0.22}. The existence of this eutectic reaction has important ramifications for the development of Ni-based electrical contacts to GaAs because any metallization scheme with a composition within the region bounded by NiGa, NiAs, and GaAs, as well as elemental Ni, will experience at least partial liquid formation at temperatures greater than 810{degree}C. {copyright} {ital 1996 American Institute of Physics.}
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-07-01
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 80
Issue Number 1


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