Reactivity and interface chemistry during Schottky-barrier formations: Metals on thin native oxides of GaAs investigated by x-ray photoelectron spectroscopy

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Abstract
The room-temperature interfacial chemical reactions of overlayers of several diverse metals (Au, Cu, Al, Mg, Cr, and Ti) with thin native oxide films (∼10 Å) on GaAs (100) surfaces were investigated with x-ray photoelectron spectroscopy (XPS). The reactivity of these metals with the native oxides of GaAs ranged from inert to complete reduction for the oxides and is well predicted by bulk thermodynamic free energies of formation. Variations in band bending during Schottky-barrier formation were monitored by XPS. The implication of the observed interface chemistry for Schottky-barrier modeling is discussed.