Process modeling of point defect effects in Hg_1-xCd_xTe

Abstract

A model is presented which describes the motion of and interactions among some of the native point defects and foreign impurities in Hg_1-xCd_xTe. Semi-quantitative simulations of typical process problems are performed for cases where only Hg interstitials, Hg vacancies, and cation impurities are important. Results for the formation of n-on-p junctions by the Hg anneal of high vacancy concentration material, indicate that junction depths may be a significant function of the n-type dopant concentration. For the case where low vacancy, n-type material is annealed in a Hg-poor ambient, simulation results confirm the difficulty in forming a high quality, well-defined p-on-n junction. This difficulty arises because of the generation of Hg vacancy/interstitial pairs throughout the bulk during most of the process. It is demonstrated that impurity gettering can be described by our modeling approach. All simulation results attempted to date are consistent with the available experimental data.