Electrical and microscopic characterization of p+-type layers formed in HgCdTe by arsenic implantation

Abstract

The Hall-effect (with mobility spectrum analysis) and capacitance measurements were combined with transmission electron microscopy for the study of molecular-beam epitaxy-grown n-type Hg1-xCdxTe (x = 0.22) films subjected to various operations used in the fabrication of p +-n photodiode structures. The operations included arsenic ion implantation, activation annealing and extra annealings aimed at investigation of the details of the p +-n junction formation. A detailed characterization of p+-type layers formed by the implantation was done. A high degree of arsenic activation by activation annealing was demonstrated, along with the annihilation of implantation-induced extended (dislocation loops) and quasi-point defects, and the disappearance of electrically active centres associated with them. The annealing was also shown to cause the activation of residual acceptors, changing the degree of electrical compensation in the n-‘base’ of some of the p +-n structures.