7.5µm and 5µm pitch IRFPA developments in MWIR at CEA-LETI

We present CEA-LETI's recent work on very small pitch HgCdTe focal-plane-arrays (FPA): materials, diode processing, readout circuit (ROIC) optimization and hybridization, done in the context of the common laboratory with SOFRADIR called DEFIR. We report on a 7.5μm pitch 640×512 FPA and a smaller 5μm pitch 64×152 FPA operating in middle wave infrared range (MWIR). The diode technology is n-on-p processed onto LPE grown HgCdTe. We will describe the two readout integrated circuits (ROIC) developed for 7.5μm and 5μm pitches and present the characterization of the IRFPAs hybridized to those ROICs. For these very small pitch detectors, we designed classic snapshot Direct-Injection (DI) Integrate-While-Read (IWR) ROICs that maximize the charge handling capacity by significantly increasing the dynamic range. For the 7.5μm ROIC, dedicated electronics has been embedded to measure the ROIC cross-talk. The 7.5μm pitch IRFPA operating at 110K displays nonlinearity under 0.5% across the maximum dynamic range, a full-well of 3.1 Me- with a 3.8V dynamic range, a ROIC noise of 210μV and SNR of 62 dB and NETD (Noise-Equivalent Temperature Difference) of 25 mK for an average current of 30 pA, and a responsivity of 1.3 pA/K.