Low Barrier Height and Nonuniformity in Al Schottky Contacts on Chemically Etched n-GaAs

The barrier height of Al Schottky-contacts on chemically etched n-GaAs has been relatively low in the as-deposited state but increased by low temperature (50-200°C) annealing. The photoresponse analysis has revealed that the asdeposited Al/n-GaAs interface consisted of the so-called parallel contact with low (0.7 eV) and high (0.9 eV) barrier heights. The dissociation of the lower barrier phase upon annealing has corresponded to the increase in the apparent barrier height determined by the I-V and C-V measurements. The native oxide could be responsible for the lower barrier phase in Al/n-GaAs Schottky diodes fabricated by a standard process.