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Prototypes of VO2-based bolometric detectors with lateral dimensions of 25 X 25, 30 X 30, 35 X 35, 40 X 40 and finally 50 X 50 micrometers2 and fill factors approaching 90% are presented. These detectors are grouped in hardwired linear arrays as large as 512 X 1 pixels. Under DC biasing, the fabricated detectors, even the smallest ones, exhibit responsivities from 48,000 to 120,000 VW-1, detectivities in the range of 1.5 X 108 cm Hz1/2W-1 and response times in the range of 5 ms. These new bolometric detector structures contain hidden-legs placed completely underneath the bolometer platform. Results of simulations of the mechanical, optical and electrical properties of these new detector structures are presented. A complete detector fabrication process flow is described.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Several prototypes of individual VO 2 -based bolometric detectors and their arrays consisting of 64 by 64, 128 by 128 and 240 by 320 pixels are presented. The fabrication method and the device characterization results are described. Three types of readout integrated circuits for the arrays are also presented. A custom vacuum package for the IR bolometric detector arrays is descried.

Uncooled IR bolometric detectors fabricated using surface silicon micromachining are presented. The detector fabrication process employs a polyamide sacrificial layer, and a VO2 thermistor layer exhibiting a thermal coefficient of resistance on the order of -3 percent/degrees C. Detector sizes are 100 micrometers X 100 micrometers and 50 micrometers X 50 micrometers , and 64 X 64 and 128 X 128 pixel arrays are fabricate. The detectors exhibit responsivities of up to 15 000 VW-1, normalized detectivities typically exceeding 108 cm Hz1/2W-1, and response times below 20 ms. Three integrated readout circuit designs for 64 X 64 and 128 X 128 pixel detector arrays, fabricated using a standard 1.5 micrometers CMOS process,a re described. These circuits include several test and detector nonuniformity correction features and can operate in either self scanning mode at a rate of 30 frames per second, or in the random access mode in which column and row addresses are input directly.

Bulk silicon micromachined IR bolometer detectors operating at room temperature are presented. These devices are based on VO2 films typically exhibiting a thermal coefficient of resistance of the order of -3%/ degree(s)C. Detector sizes are 50 micrometers X 50 micrometers and 100 micrometers X 100 micrometers , and they are arranged in 1 X 64, 1 X 128 and 1 X 256 pixel linear arrays. A test bench for detector performance evaluation is described. The fabricated detectors exhibit responsivities of up to approximately 20,000 V/W, normalized detectivities typically exceeding 108 cmHz1/2 W-1, and response times typically below 20 ms, At 300 K and a frequency of 30 Hz, the noise equivalent temperature difference for these detectors is of the order of 3 X 10-2 degree(s)C. A bolometer simulation tool is also briefly described.