256 x 256 3- to 5-um focal plane array at 77 K operation

A 256 by 256 IRCMOS array with a 35 micrometer pitch operating in the (3 - 5) micrometer wavelength range at 77 K has been developed at LETI/LIR. The readout circuit was designed and processed with a 1.2 micrometer design rules standard CMOS technology. Photovoltaic (PV) detectors, made on liquid phase epitaxy (LPE) layers, are interconnected by indium bumps on the readout circuit. A description of the readout circuit is given and the main electro-optical characteristics of the component are presented. The detector arrays exhibit a quantum efficiency of 60% with a non-uniformity of less than 4%. The pixel operability is greater than 99.5 %. In spite of the non-optimized threshold voltage of the technology, the charge handling capacity reaches 20.10 6 e - for the 35 micrometer pitch. This allows an NEDT of 12 mK at the output midpoint. Excellent imagery has been obtained with this component operating at 77 K using f/2 optics. The imagery has high contrast with no significant fixed pattern noise.