HgCdTe photodiode arrays passivated by MBE in-situ grown CdTe film

Abstract

The results of HgCdTe long-wavelength infrared n+-on-p planar photodiode arrays passivated by molecular beam epitaxy(MBE) in-situ grown CdTe film were presented in this paper.By mercury-vacancy p-type annealing,ion-implantation window exposure,ZnS ion-implantation barrier layer deposition,B+-implantation,ion-implantation barrier layer removal,ZnS dielectric film deposition,metallization and indium-bump arrays fabrication,HgCdTe long-wavelength infrared n+-on-p planar photodiode arrays using in-situ CdTe passivation was achieved from a Hg1-xCdxTe film covered with a layer of MBE in-situ grown CdTe film.Zero bias dynamic resistances of HgCdTe photodiode arrays using in-situ CdTe passivation were improved 1~2 times higher than those of non-in-situ CdTe passivation processed one,and the maximum dynamic resistances near small reverse biases were even increased by a factor of 30~40.Since their current-voltage curves were all measured at 78K,it is obvious that in-situ CdTe passivation was beneficial to suppress dark current of n+-on-p planar photodiode by optimizing the interface between the HgCdTe detector and CdTe passivation layer,and then to enhance the performance of long-wavelength infrared photodiode arrays operating at small reverse biases.