Design of a small pitch (7.5µm) MWIR HgCdTe array operating at high temperature (130K) with high imaging performances

SWAPc (Size, Weight And Power-cost) is a strong trend in IR imaging systems. It requires focal plane arrays with smaller pixels, operating at high temperatures. For MW systems, the full spectral band (up to 5μm) shows a strong advantage over the blue band (4.1µm) as it maximizes the number of incoming photons from a room temperature scene. Few years ago, LETI and Lynred have been developing 7.5μm pitch MCT arrays in MW full band. The first version of this technology was based on n/p diodes operating at 110K maximum temperature. Switching to p/n using extrinsic doping allows today an important gain in dark current, enabling operating temperature up to 130K or even higher. This paper will describe our latest results in the design and fabrication of such HOT small pitch arrays, starting with test chip arrays, followed by the full the characterization of 1280×1024 7.5μm pitch arrays. First order figure of merit (dark current, QE…) are of course considered, but second order figure of merit will also be discussed such as noise tails.