Mechanism for nearly ohmic behavior in annealed Au/n-GaAs Schottky diodes

R. P. Leon, Nathan Newman, Z. Liliental-Weber, E. R. Weber, J. Washburn, W. E. Spicer

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Abstract

The origin of the ohmic behavior observed after annealing Au/n-GaAs {110} Schottky diodes was investigated by electron-beam-induced current (EBIC) measurements of diode plan views and cross sections, combined with standard scanning electron microscopy and transmission electron microscopy techniques. The large leakage currents responsible for this behavior arise at the periphery of the deposited gold films, where elongated gold crystallites which lie on the GaAs surface are observed after heat treatment. These crystallites are typically 2-5 μm long, 500-2000 Å wide, and are crystallographically oriented along the GaAs [110] direction. EBIC imaging demonstrated that a space-charge region was present under the peripheral area showing the gold crystallites. Comparison of current collection as measured with EBIC between annealed and unannealed diodes shows a large reduction in current collection under and around the periphery of the annealed diodes. These data allow attribution of the ohmic behavior to a recombination current. Experiments done with overlapping Au evaporations show that recombination on the bare GaAs surface between the observed crystallites surrounding each annealed diode is the main component of this recombination current, and thus of the large leakage current.

Original languageEnglish (US)
Pages (from-to)711-715
Number of pages5
JournalJournal of Applied Physics
Volume66
Issue number2
DOIs
Publication statusPublished - 1989
Externally publishedYes

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ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Leon, R. P., Newman, N., Liliental-Weber, Z., Weber, E. R., Washburn, J., & Spicer, W. E. (1989). Mechanism for nearly ohmic behavior in annealed Au/n-GaAs Schottky diodes. Journal of Applied Physics, 66(2), 711-715. https://doi.org/10.1063/1.343543