QWIP from 4μm up to 18μm

Abstract

Standard GaAs/AlGaAs Quantum Well Infrared Photodetectors (QWIP) are considered as a technological choice for 3 rd generation thermal imagers [1], [2]. Since 2001, the THALES Group has been manufacturing sensitive arrays using AsGa based QWIP technology at THALES Research and Technology Laboratory. This QWIP technology allows the realization of large staring arrays for Thermal Imagers (TI) working in the Infrared region of the spectrum. The main advantage of this GaAs detector technology is that it is also used for other commercial devices. The GaAs industry has lead to important improvements over the last ten years and it reaches now an undeniable level of maturity. As a result the key parameters to reach high production yield: large substrate and good uniformity characteristics, have already been achieved. Considering defective pixels, the main usual features are a high operability (> 99.9%) and a low number of clusters having a maximum of 4 dead pixels. Another advantage of this III-V technology is the versatility of the design and processing phases. It allows customizing both the quantum structure and the pixel architecture in order to fulfill the requirements of any specific applications. The spectral response of QWIPs is intrinsically resonant but the quantum structure can be designed for a given detection wavelength window ranging from MWIR, LWIR to VLWIR.