MIS STRUCTURES ON HG1-XCDXTE/CDTE/GAAS EPILAYERS

A plasma-anodization process is used for the growth of homogeneous oxide films (300-600 Å) on vapor-phase epitaxy grown p-type Hg1-xCdxTe. The relative dielectric constant of the oxide film is 10 as obtained from the current-voltage characteristic of metal-oxide-semiconductor (MOS) devices. Capacitance-voltage (C-V) measurements performed with MOS structures reveal the density of fixed positive oxide charges (N0=2x1012 cm-2). C-V measurements with metal-insulator-semiconductor (MIS) devices, with an insulator consisting of the native oxide and evaporated ZnS, are used to determine the doping level and the band gap of the Hg1-xCdxTe layer as well as the density of localized states at the semiconductor-oxide interface. Measurements of admittance spectroscopy with MIS structures on Hg1-xCdxTe are reported. Admittance spectroscopy identifies a hole trap located 0.4Eg above the valence-band edge. The trap density and the majority carrier cross section of this trap is obtained. © 1989.