CdZnTe heteroepitaxy on 3″ (112) Si: Interface, surface, and layer characteristics

Abstract

Tellurium adsorption studies were made on clean and arsenic passivated (112) silicon surfaces. Quantitative surface coverage values for tellurium were determined by Auger electron spectroscopy. Saturation coverage of up to 1.2 monolayers of tellurium could be obtained on a clean (112) silicon surface. On an arsenic passivated (112) Si surface however, the tellurium saturation coverage was limited to only ∼0.3 monolayer. Analysis of the adsorption behavior suggested that tellurium and arsenic chemisorption occurs preferentially at step edges and on terraces, respectively. The study revealed that arsenic passivation led to a significant decrease in the sticking coefficient of tellurium and an increase in it’s surface mobility. A model describing zinc telluride nucleation on a (112) Si surface is proposed. Thin templates of ZnTe followed by Cd1−xZnxTe layers were deposited on (112) Si by molecular beam epitaxy (MBE). The characteristics of the MBE Cd1−xZnxTe layers were found to be sensitive to the initial ZnTe nucleation and Si surface preparation.