Technology Development of Microbolometer IRFPA Detectors

• Main Authors: Chung-Nan Chen, 陳忠男
• Other Authors: Jin-Shown Shie
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/70658672064499045597

博士 === 國立交通大學 === 光電工程所 === 88 === In this thesis, fabrication and characterization of CMOS-process-compatible microbolometer IRFPAs detectors are explored. These monolithic IRFPAs made of metal and semiconductor films and having thermally isolated structures are fabricated by combining IC process with bulk micromachining technique. The resistivity, TCR, noise and responsivity of single microbolometers of various material films have been fabricated and measured, which performances were characterized by calculating the D* and NETD for proposed IRFPA detectors. In the studies, platinum, germanium and polysilicon thin films are used as the sensing materials. The platinum films shows TCR values of 0.27, 0.28 and 0.31 %/oC with 200, 500 and 1000 A thickness, respectively. For germanium, TCR is ranged from -0.1 to -4.5 %/ oC with various annealing conditions. While for polysilicon thin films, TCR values extended from -0.01 to -5.9 %/ oC with different impurity dosage. Our noise measurement found that single Pt bolometer exhibits only Johnson noise, but germanium and polysilicon sensors show significant 1/f noise over their Johnson noise. Our experiment shows that one of the fabricated germanium bolometers has voltage responsivity of 7000 and 400000 V/W in air and vacuum, respectively, with proper annealing around 370 oC. The values of D* and NEDT of various proposed IRFPA detectors, based on our measured results and the design rule of a 1.2 m CMOS-process, are also calculated theoretically. It shows that the Pt IRFPA detector has the best performance in the three materials. The processes are designed to be compatible with the standard CMOS process in current IC foundries make it possible to commercialize the IRFPA devices with low cost and high reliability in the future.