Megapixel HgCdTe MWIR focal plane array with a 15-μm pitch

In this paper we present the first demonstration at LETI infrared laboratory of a megapixel HgCdTe MWIR focal plane array with a 15μm pitch. The detectors were interconnected by indium bumps to the CMOS readout circuit. The design of these interconnections has been adapted from the standard CEA-LETI process to achieve resolution and uniformity required by the reduced pitch. Because of the mismatch of thermal dilatation coefficients between the substrate and the HgCdTe, specific developments were necessary in order to achieve the hybridization process with an extremely reduced amount of defaults. The readout circuit was designed in a 3.3V /0.35μm CMOS technology. Its main features were to allow the validation of the hybridization and technological processes. A Megapixel IRCMOS has been fully characterized at 77K exhibiting excellent electro-optical performances and an operability greater than 99.8%.