Thermal stability of the anodic oxide/Hg_1−xCd_xTe interface Available to Purchase

We have studied the stability of the anodic oxide/Hg_1−xCd_xTe interface upon annealing with the aid of electrical capacitance–voltage (C–V) measurements, the thermodynamic properties of the Hg–Cd–Te–O system, and Auger sputter profiles. The C–V measurements on metal–insulator–semiconductor (MIS) devices showed a large increase in the positive fixed charge and slow interface traps as well as a conversion from p type to n type upon annealing at 100 °C. The equilibrium phase diagram predicted that any oxide containing Hg and a Te:Cd>1 at the interface will be unstable and react with the Hg_1−xCd_xTe substrate to form HgTe, Hg, Te, as well as lower x value Hg_1−xCd_xTe with subsequent degradation of electrical device characteristics. The Auger sputter profiles of thermally stressed oxide films (170 to 220 °C) gave support for these interface reactions with measurements of an enhanced Cd layer (∼150 Å) in the oxide and an enhanced Hg and depleted Cd layer (∼240 Å) in the substrate near the interface.