Ion implantation in ZnTe: Defect generation, migration and annealing

Abstract

The effect of the implantation of ions of various natures (N, O, Al, Tl) in ZnTe crystals has been investigated by means of electrical and optical techniques. We show that ion implantation as well as sputtering leads to generation and migration of electrically active defects over thousands of Angstroms or microns farther than the projected range of the implanted ions. Anneals in saturated Zn vapour allow (1) the disappearance of most of the implantation defects at 300–400°C (2) the formation of a new compensated zone by surface generation and migration of intrinsic donor defects (or out-diffusion of the native acceptors) in the 500–550°C range. The temperature at which the implanted ions go into substitutional lattice sites and the nature of the defect- impurity interactions is a particular problem for each ion. The case of the cathodoluminescence efficiency of implanted Al ions is more particularly investigated.