MBE原位碲化镉钝化的碲镉汞长波光电二极管列阵

摘要

采用分子束外延(MBE)技术在表面生长碲化镉(CdTe)介质膜的p型碲镉汞(HgCdTe)材料,并通过离子注入区的光刻、暴露HgCdTe表面的窗口腐蚀、注入阻挡层硫化锌(ZnS)的生长、形成p-n结的B+注入、注入阻挡层的去除、绝缘介质膜ZnS的生长、金属化和铟柱列阵的制备等工艺,得到了原位CdTe钝化的n+-on-p平面型HgCdTe红外光电二极管列阵.从温度为78 K的电流与电压(I-v)和动态阻抗与电压(R-v)特性曲线中,发现原位CdTe钝化的光电二极管列阵的零偏动态阻抗比非原位CdTe钝化的提高了1～2倍,零偏压附近的反向偏压位置的动态阻抗极大值甚至提高了30～40倍.对于工作在反向小偏压附近的光电二极管列阵,原位CdTe钝化方法非常有利于提高长波光电二极管的探测性能.%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-xCdx Te 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.