Semi-insulating CdTe with a minimized deep-level doping

The possibility to prepare semi-insulating CdTe with a deep-level doping below the limit 10(13) cm(-3) demanded in detector industry is studied theoretically within quasi-chemical formalism. We show that proper thermal treatment, including low temperature (ca 200 degrees C) dwell, allows fulfillment of this demand also in 7N or less purity materials. The procedure is demonstrated in Te-rich CdTe doped with a shallow donor. Its principle is based on enhanced defect self-compensation, which affords at sufficiently low temperature extremely high compensation of shallow defects. New high-temperature transport data are used to refine on previous native defect properties for the modeling. The analysis of diffusion rates at lowered temperature approves the model for a real-time experimental verification.