Effect of post-implantation annealing on the current-voltage characteristics of IR photodiodes based on p-HgCdTe

Current-voltage characteristics of IR photodiodes and distributions of charge carriers in n+-n−-p-structures based on vacancy p-doped Hg1 − xCdxTe films with x = 0.22 are examined. Three-dimensional numerical modeling of the distribution of charge carriers and current-voltage characteristics during photodiode annealing is performed. The calculations predict that large tunnel currents in diodes after implantation can result from an elevated (more than 1015 cm−3) concentration of donors in the n−-layer, which enhances tunneling by decreasing the thickness of the space charged region of the n-p-junction, and also from a small (less than 3 µm) depth of the p-n-junction.