320x240 Microbolometer Focal Plane Array For Uncooled Applications

SBRC has developed a high-quality 320 X 240 room-temperature infrared FPA that operates in the 8 - 14 micrometers spectral band. The FPA is based upon the silicon microbolometer technology that has been licensed from Honeywell. This monolithic uncooled FPA utilizes a novel BiCMOS readout circuit that provides high sensitivity and excellent output uniformity. The 320 X 240 FPA operates at frame rates up to 60 Hz with a single output. The microbolometers were fabricated monolithically on the silicon readout circuits at SBRC using VOx as the bolometer material. An advanced microbridge structure design was used that achieves an optical fill-factor greater than 65% in the 48 micrometers X 48 micrometers pixels. The structure also provides excellent thermal isolation for high responsivity and sensitivity. Initial measurements indicate the FPAs are operating with an NETD sensitivity of about 100 mK for an f/1 aperture. This FPA is ultimately expected to operate at sensitivities of less than 20 mK. The FPA also demonstrate peak-to-peak output nonuniformities of less than 100 mV. The FPAs have been mounted in permanently-sealed vacuum packages with single- stage thermoelectric temperature stabilizers. These vacuum packages have been integrated into a camera system that has produced high-quality infrared imagery.