In-Vacuo Passivation of High Aspect Ratio HgCdTe Surfaces

As HgCdTe technology has evolved, many of the devices used in infrared detector applications have required the creation of high-aspect-ratio morphologies. Therefore, equally important to the creation of these high-aspect-ratio geometries is the ability to subsequently deposit the necessary materials on these surfaces. To ensure ideal device performance, the material deposition must be uniform, conformal and free of pinholes. One of the most critical deposited materials in these infrared devices is the passivation layer. While many types of passivation materials for HgCdTe have been investigated, one of the most common and promising is CdTe. EPIR Technologies proposes the use of the ALD (Atomic Layer Deposition) process to grow CdTe passivation layers. The ALD process represents an optimization of the conventional chemical vapor deposition process. The ALD process will provide a passivation layer conformality improvement over existing deposition methods. Superior film quality also will be possible due to ALD’s ability to encapsulate point defects. The ultimate goal of this project is to develop uniform, conformal, pinhole free CdTe passivation layers required for HgCdTe infrared devices. The feasibility of employing an ALD process to deposit CdTe passivation layers on high-aspect-ratio surfaces will be demonstrated during Phase I.