Pd-on-GaAs Schottky Contact: Its Barrier Height and Response to Hydrogen

A Pd-on-GaAs Schottky contact was prepared by depositing palladium using a tungsten heater, rather than electron-beam heating, onto a GaAs surface. The interface composition was investigated by sputter Auger electron spectroscopy. An intermediate layer resulting from the reaction of Pd and GaAs was observed under certain conditions. The Schottky barrier height estimated from the measurements of forward current-voltage (I-V) or reverse capacitance-voltage (C-V) characteristics was found to depend on the interface structure. The response of the Schottky contact to hydrogen was found to be correlated with the barrier height. We pointed out that hydrogen can be used as a probe to the interface structure, whether metallic Pd or an intermediate material of Pd-Ga-As is in contact with GaAs. The observation was consistent with both p- and n-type GaAs.