Plasma anodization of Hg1−xCdxTe

A new plasma oxidation process for forming oxide films on Hg1−xCdxTe is described. Electrical measurements on metal-insulator-semiconductor devices employing the native oxide are presented. The oxide films have a relatively low fixed surface charge density of (1–3)×1011 e cm−2 and in this respect are superior to oxides growth by chemical anodization. For insulators which are a combination of 300-Å native oxide and 2000-Å ZnS the measured flat-band voltages are −0.5 and −2.5 V for n-t and p-type substrates, respectively. The measured work-function difference is −1.7 V for indium gate structures and the relative dielectric constant of the oxide is 13. The capacitance-voltage and current-voltage characteristics indicate an interface well suited for devices such as photoconductors, photovoltaic diodes, and charge-coupled devices.