Low-Pressure Chemical Vapor Deposition of CdS and Atomic Layer Deposition of CdTe Films for HgCdTe Surface Passivation

HgCdTe narrow-bandgap materials are used in the fabrication of infrared detectors and focal-plane arrays. Many of these advanced devices require complex structures to be processed into them. Passivation of planar detectors is typically done with vacuum-evaporated CdTe or related II–VI materials. New advanced detector topology necessitates the use of low-pressure chemical vapor deposition (LPCVD) and atomic layer deposition (ALD) for improved conformal coverage. Preliminary studies on LPCVD of CdS and ALD of CdTe were carried out and characterized for conformal coverage. The effects of CdS and CdTe films on HgCdTe minority-carrier lifetime are also studied at 300 K and 77 K.