INDIUM OXIDE SCHOTTKY JUNCTIONS WITH INP AND GAAS

Junctions of transparent conducting oxides on III-V semiconductors hav e been prepared by deposition of indium oxide layers onto p-type InP a nd n-type GaAs by means of reactive evaporation of In in the presence of oxygen at different substrate temperatures. The electrical proper-t ies and chemical composition of these junctions have been investigated using current-voltage measurements in the dark at room temperature, c apacitance-voltage measurements, and depth profiling by Auger electron spectroscopy. The best diodes were obtained by deposition at a substr ate temperature near 250-degrees-C and oxygen pressure of 5 X 10(-4) T orr. These diodes exhibit a Schottky barrier height of 0.80 eV for n-t ype GaAs and 0.87 eV for p-type InP with an ideality factor of 1.04. T he Schottky barrier height decreases with decreasing deposition temper ature for both substrates. The roles of the tunneling-transparent inte rface layer and interface region are theoretically considered. It is s hown that as the deposition temperature is increased, the barrier heig ht increases due to the accompanying reduction in the density of surfa ce states, which are induced by elemental In at the interface.