DESIGN AND DEVELOPMENT OF A SUSPENDED BRIDGE AND THERMAL ISOLATION STRUCTURE FOR MICROBOLOMETER IRFPA

Abstract

The microbolometer based detector has been attaining huge prominence due to their improvements in performance parameters, small size, economy and uncooled operation. Currently, it has been extensively utilized in night vision systems, firefighting applications, detection of gas leakage in industries, security surveillance, and medical monitors due to its application under disapproving circumstances like heavy rain, foggy weather or snow fall. Imaging and detection is based upon absorption of IR radiations. When infrared light strikes the sensor, bolometer changes its resistance due to variation in temperature. For night vision imaging applications microbolometer based sensor operated at room temperature has gained much attraction. A compact and stable suspended micro-bridge structure for high resolution thermal IR imaging sensors is presented in this report. The suspended bridge supporting pillars and biasing contacts have been placed under the active layer to make the microbolometer more compact and robust. Thermal conductivity of the cell can be well controlled by varying pillar size and their number without affecting the sensing area