Progress toward an uncooled IR imager with 5-mK NETD

The bi-material concept for room-temperature infrared imaging has the potential of reaching an NE(Delta) T approaching the theoretical limit because of its high responsivity and low noise. The approach, which is 100% compatible with silicon IC foundry processing, utilizes a novel combination of surface micromachining and conventional integrated circuits to produce a bimaterial thermally sensitive element that controls the position of a capacitive plate coupled to the input of a low noise MOS amplifier. This approach can achieve the high sensitivity, the low weight, and the low cost necessary for equipment such as helmet-mounted IR viewers and IR rifle sights. The pixel design has the following benefits: (1) an order of magnitude improvement in NE(Delta) T due to extremely high sensitivity and low noise; (2) low cost due to 100% silicon IC compatibility; (3) high image quality and increased yield due to ability to do offset and sensitivity corrections on the imager, pixel-by-pixel; (4) no cryogenic cooler and no high vacuum processing; (5) commercial applications such as law enforcement, home security, and transportation safety.