Direct variation of metal-GaAs Schottky barrier height by the influence of interface S, Se, and Te

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Abstract
The electrical properties and interface chemistry of Schottky barrier contacts (Ag, Al, Au, Mn, Pd, and Ti) formed on n-type GaAs (100) surfaces that had prior exposure to elemental S, Se, and Te are compared to those of ideal (metal deposited onto a clean surface) contacts. The interface Fermi energy EiF and interface chemistry during contact formation were investigated by x-ray photoemission spectroscopy; the accompanying Schottky barrier height φB was measured by current-voltage and capacitance-voltage techniques. A substantial decrease in φB (and correlated change in EiF ) for Al and Mn contacts is associated with a contact metal-chalcogen chemical reaction at the Schottky barrier interface, while some nonreactive noble metal-chalcogen interfaces have a φB increase. By choice of contact metal and interface chalcogen a φB range of >0.6 eV is obtained (∼0.35 to 1.0 eV, which is >40% of the GaAs band gap) via corresponding changes in EiF.