Performance of microbolometer focal plane arrays under varying pressure

• Published in: IEEE electron device letters Vol. 21; no. 5; pp. 233 - 235
• Main Authors: He, X., Karunasiri, G., Mei, T., Zeng, W.J., Neuzil, P., Sridhar, U.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-05-2000; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Air gaps; Arrays; Biomembranes; Bolometers; Circuits; Fabrication; Focal plane; Image contrast; Low pressure; Micromachining; Microorganisms; Pressure; Resistors; Switches; Thermal conductivity
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/55.841306

In this letter, we present a study of imaging using a 128/spl times/128-pixel microbolometer focal plane array (FPA) under varying pressure conditions from 10/sup -5/ torr to the ambient. We have employed bulk micromachining in the fabrication of FPA to reduce the thermal conduction through the air-gap between the membrane and the substrate of the microbolometers. It was found that an image of a soldering iron (200/spl deg/C) was clearly visible even at the ambient pressure. However, at ambient pressure, the increased in thermal conductance resulted in a reduction of contrast of the image compared to the ones obtained at low pressure. The results suggest the possibility of operation of uncooled FPA's under ambient pressure by proper design of the microbolometer structure.