Abstract
ABSTRACTThe structure and electrical properties of Au contacts to GaAs have been studied by analytical and high-resolution transmission electron microscopy (TEM) combined with electrical characterization and photoemission spec-troscopy (PES). The contacts were prepared by in-situ deposition of Au onto ultra-high vacuum cleaved n-GaAs (110) surfaces. The effects of annealing on the electrical, morphological and chemical properties of the Au:GaAs contacts were studied. It was shown that the formation of Schottky contacts is correlated with the change in stoichiometry of the GaAs substrate near the Au/GaAs interface. The change to ohmic behavior for the samples annealed above Au-Ga eutectic was explained by leakage currents at the periphery of the devices. TEM micrographs of the structures revealed the existence of elongated Au crystallites on the GaAs surface at the periphery of the contacts. These leakage currents were eliminated by removing the current path at the periphery using a mesa-etch.
Published Version
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