SIMULATION OF HGTE CDTE INTERDIFFUSION USING FUNDAMENTAL POINT-DEFECTMECHANISMS/

A numerical model for interdiffusion in HgTe/CdTe systems based on Fun damental paint defect mechanisms has been developed. The model include s continuity equations for the flux of Hg and Cd on substitutional sit es, cation vacancies, and Hg and Cd interstitials. Interdiffusion is m odeled by simulating the coupled diffusion and interaction of these sp ecies. The Hg vacancy concentration used in the model was fit to measu red hole data as a function of annealing temperature, Hg pressure, and composition. The Cd and Hg interstitial diffusion coefficients and co ncentrations were determined as a function of temperature and composit ion from low temperature Hg and Cd self-diffusion data. With this mode l, interdiffusion is simulated over a range of initial and annealing c onditions. At high temperatures and/or Te saturated conditions, interd iffusion is dominated by diffusion via a vacancy mechanism. Interdiffu sion is controlled by the flux of Cd interstitials at lower temperatur es and/or higher Hg pressures.