The effect of low temperature annealing on defects, impurities, and electrical properties of (Hg,Cd)Te

Many methods for the preparation of (Hg,Cd)Te alloys rely on a low temperature processing step to convert the as‐grown p‐type material to n‐type, or to otherwise adjust the concentration of native acceptors. During this anneal, tellurium precipitates in the material are annihilated by in‐diffusing mercury, resulting in a substantial multiplication of dislocations. For substantially long anneals (>1 day at 270 °C) the depth of the p–n junction is found to vary as the square root of the anneal time and inversely as the square root of the excess tellurium concentration. Rapidly diffusing impurities such as silver are gettered out of the skin and into the remaining vacancy‐rich core. The kinetics of these processes are analyzed for self‐diffusion on the metal sublattice involving only vacancies, only interstitials, and for a mixed vacancy–interstitial model. Comparison with experimental data shows best agreement with the mixed interstitial–vacancy model.