QWIP and 3rd generation IR imagers

Abstract

Standard GaAs/AlGaAs Quantum Well Infrared Photodetectors (QWIPs) are from now seriously considered for the 3rd generation of IR imagers. Since 2002, the THALES Group has been manufacturing sensitive arrays using QWIP technology based on AsGa techniques through THALES Research and Technology Laboratory. This QWIP technology allows the realization of large staring arrays for Thermal Imagers (TI) working in the IR band III (8-12 μm). A review of the current QWIP products is presented. In the past researchers claimed many advantages of QWIPs. Uniformity was one of these and was the key parameter for the production start. By presenting our first results of a 640x512 LWIR FPA at a pitch of 20μm, we also demonstrate that very high performances can be achieved even with small pixels which opens the field for the realization of usable and affordable megapixel FPAs. Another advantage widely claimed in the past for QWIPs was the so-called band-gap engineering and versatility of the III-V processing. This allows the custom design of quantum structure to fulfill the requirements of specific applications like very long wavelength or multispectral detection. In this presentation, we present the performances of our first 256x256 MWIR / LWIR and LWIR/LWIR two color FPAs at a pitch of 25 μm.