Modification of HgCdTe–Native Oxide Interface by Annealing

Abstract

The interface properties of Hg 1-x Cd x Te (MCT) with native oxide (NO) after annealing at various stages of MIS device (Me-Si 3 N 4 -SiO 2 -NO-MCT (p-type)) fabrication have been investigated. Heat treatments were provided in vacuum and in the atmosphere at temperatures of 100 to 130 °C before and after native oxide formation and after deposition of SiO 2 overcoated with Si 3 N 4 . The fixed charge value in the oxide varied from -2.5 × 10 11 cm -2 to +5 × 10 11 cm -2 in dependence on the annealing conditions. At the same time the amount of interface traps and near-surface bandgap states changed. It is assumed that these changes are caused by mercury migration at heating. The vacuum annealing of the oxidized samples before deposition of the dielectric layers significantly improves the MCT-insulator interface properties.