Physical and chemical properties of the anodic oxide/HgCdTe interface

Abstract

In this paper we show that anodic oxide/Hg0.8Cd0.2Te interface is a two-layered structure with a thin CdTeO3 layer next to the Hg0.8Cd0.2Te substrate and a second thicker layer of CdTeO3, TeO2, HgTeO3, and HgTe particles. For a 700-Å-thick anodic oxide, the thin CdTeO3 layer was 30–50 Å thick and the second interface layer was ∼120–150 Å thick. The large positive fixed charge measured on metal-insulator semiconductor devices which have been fabricated with the anodic oxide may be caused by a large concentration of positively charged oxygen vacancies associated with the HgTe particles in the second interface layer. The low interface trap densities are probably due to the thin CdTeO3 layer which forms a good interface with HgCdTe.