Boron and indium ion-implanted junctions in HgCdTe grown on CdTe and CdTe/Al2O3

Abstract

This paper discusses the results of junction formation in p-type HgCdTe material which has been converted into n type by ion implantation processes. In was chosen as the candidate donor impurity because it has been observed to diffuse from the implanted source and to activate electrically in a Hg-vacancy doped material under certain anneal conditions. Our results indicate that In diffuses and activates in both Hg-vacancy doped and As-doped HgCdTe layers in both capped and uncapped with saturated Hg overpressure regardless of the background defect structure of the layer. Several apparently different diffusion mechanisms appear in In profiles giving fast, anomalous high concentration components and slow components with low concentration levels. However, under high temperature (400 °C) capped anneals, a single limited source diffusion mechanism appears to dominate (Deff=8×10−13 cm2/s). This mechanism is attributed to vacancies present in the background. Characteristics of indium implantation into arsenic-doped layers were observed in which n-type electrical activity is indium related and controllable by implant/anneal conditions. p-type electrical activity is due to arsenic and it could be controlled by adjusting the arsenic doping level during epitaxy.