MBE Growth of MCT on GaAs Substrates at AIM

Driven by the need for more efficient and cost-effective production of infrared (IR) detectors as well as the demands for novel (third-generation) device concepts, a large amount of effort has been spent on the development of molecular beam epitaxy (MBE) for fabrication of high-quality HgCdTe (MCT) layers on both CdZnTe and alternative substrates. The bulk of recent publications focuses on Si as an alternative substrate material. The intent of this paper is to highlight the potential benefit of using GaAs as an alternative substrate material by presenting MCT material grown by MBE on GaAs at AIM. Mid-wave IR MCT/GaAs material has been processed by AIM’s standard planar n-on-p technique. Focal-plane arrays with 640 × 512 pixels and a 15 μm pitch design show low and homogeneous noise equivalent temperature difference of 18.3 ± 2.0 mK at 99.31% operability. To analyze the feasibility of MBE growth of long-wave IR MCT on GaAs, a layer with 8.8 μm cutoff at 80 K has been fabricated and processed into 640 × 512 pixels, 15-μm-pitch arrays. Initial current–voltage characterization yields promising results and illustrates the potential of MBE growth for LWIR MCT detector production.