MCT-Based High Performance Bispectral Detectors by AIM

Abstract

In recent years, AIM has established molecular beam epitaxy growth of mercury cadmium telluride (MCT) on GaAs substrates for the cost-effective production of standard infrared (IR)-detectors in the mid-wave infrared (MWIR) spectral range. The most recent progress in development is to apply this technology to the fabrication of 3rd generation IR-modules. The growth of MCT multi-layers with high homogeneity in layer thickness and composition, coupled with a low defect density, is the basis of high performance multi-color IR-detectors. Applying this technology to 3rd generation IR-modules, AIM is developing short-wave/mid-wave (SW/MW) and mid-wave/mid-wave (MW/MW) infrared bispectral MCT detectors with 320 × 256 pixels and a 30 μm pitch. The sensitivity of two different IR wavelengths in one detector greatly enhances the ability to gather information from a scene, which is a significant additional benefit for IR systems. In particular, the combination of the SWIR/MWIR or MWIR/MWIR spectral bands promote an enhanced target discrimination and identification by increasing the identification range, by enabling the target acquisition in front of strongly structured backgrounds, or of targets with low thermal signature. Results will be presented on AIM’s SW/MW, as well as MW/MW bispectral MCT IR detectors. The detectors demonstrate very low color cross-talk, low defect densities, thermal resolution of about 20 mK, and high quantum efficiencies.