INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES
Issue Date:
2006
Abstract(summary):
This paper presents a monolithic uncooled 8 x 8 bolometer array with polycrystalline silicon-germanium (poly-SiGe) thermistors as active elements. The polySiGe films are deposited by ultrahigh vacuum vapor deposition (UHV/CVD) system and the dependence of the temperature coefficient of resistance (TCR) on annealing temperature has been investigated. To decrease the thermal conductance of the bolometer, the poly-SiGe thermistor was formed on a four leg suspended microbridge. The improved porous silicon micromachining techniques described here enable the integration of the bolometer array with the MOS readout circuitry. The measurements and calculations show that the mean responsivity is 1.07 x 10(4) V/W with an uncorrected uniformity of 10.5% and a thermal response time of 10.5 ms, and the detectivity of 3.75 x 10(8) cm Hz(1/2)/W is achieved at a chopping frequency of 30 Hz and a bias voltage of 5 V.