Development of High-Performance eSWIR HgCdTe-Based Focal-Plane Arrays on Silicon Substrates

Abstract

We report the development of high-performance and low-cost extended short-wavelength infrared (eSWIR) focal-plane arrays (FPAs) fabricated from molecular beam epitaxial (MBE)-grown HgCdTe on Si-based substrates. High-quality n-type eSWIR HgCdTe (cutoff wavelength ∼2.68 μm at 77 K, electron carrier concentration 5.82 × 1015 cm−3) layers were grown on CdTe/Si substrates by MBE. High degrees of uniformity in composition and thickness were demonstrated over three-inch areas, and low surface defect densities (voids 9.56 × 101 cm−2, micro-defects 1.67 × 103 cm−2) were measured. This material was used to fabricate 320 × 256 format, 30 μm pitch FPAs with a planar device architecture using arsenic implantation to achieve p-type doping. The dark current density of test devices showed good uniformity between 190 K and room temperature, and high-quality eSWIR imaging from hybridized FPAs was obtained with a median dark current density of 2.63 × 10−7 A/cm2 at 193 K with a standard deviation of 1.67 × 10−7 A/cm2.