A low-cost 64/spl times/64 uncooled infrared detector array in standard CMOS

This paper reports the development of a low-cost, 64/spl times/64 uncooled infrared focal plane array (FPA) based on suspended and thermally isolated p/sup +/-active/n-well diodes in a standard 0.35 /spl mu/m CMOS process. The array is implemented using a simple post-CMOS process that do not require any critical lithography or complicated deposition steps. The pixel is 40 /spl mu/m/spl times/40 /spl mu/m in size with a fill factor of 44%, and it has a measured DC responsivity of 4970 V/W with a thermal time constant of 36 msec at 80 mTorr vacuum. The detector noise is measured as 0.52 /spl mu/V for a 4 kHz electrical bandwidth with a 1/f corner frequency of 4.4 Hz, resulting in a measured detectivity of 9.7/spl times/10/sup 8/cm Hz/sup 1/2/W and an estimated NETD value of 470 mK for an f=1 optics. The FPA is scanned at 30 fps using a 16-channel parallel readout circuit with low noise preamplifiers. The preamplifiers have a measured noise of 0.48 /spl mu/V, resulting in an overall estimated NETD of 800 mK, which can be decreased by increasing the number of parallel readout channels. The uncompensated pixel voltage non-uniformity is measured as 0.82%, which easily decreases down to 0.05% by compensating the fixed pattern noise. Considering its simple fabrication method and its moderate performance, this approach is suitable for low-cost commercial infrared imaging applications.