Study On Uncooled Infrared Detecetor With Vertical Conduction Structure

With the development of ultra large scale integration circuit and the technology of MEMS,infrared detector technology has made remarkable progress; commercial applications in thefield of military and civilian has appeared. Though the price of uncooled infrared detector islower than that of cooled infrared detector, the performance of uncooled infrared detectorhas huge disparity, which hindering its application in the field of high-end fields.Researchers are pursuing in improving detection performance of uncooled infrared detectorsto reach background limited detection.This thesis proposes a scheme to use high resistivity and high TCR material ofvanadium oxide sandwiched between two pieces of metallic films or conductive metalcompound thin films as infrared absorption sensing structure. This structure forms a verticalelectrical conduction path for the infrared detector. The works in this thesis are composed ofthe following points:(1) Under the approximation of uniform conductivity inside the thin films for multilayersystem, TCR formula of these films is obtained to analyze the feasibility of using highresistivity sensitive material to have a high TCR in metal/semiconductor/metal stackedstructure;(2) Infrared absorption properties of vertical conductance structure with three-layerstacked films are analyzed by using transfer matrix method. By comparison of metal ormetallic oxide as the surface conductive layer for vertical conductance structures, it is foundmetallic oxide like ITO has proper thickness for deposition than using metal. Furthermore,the conductivity of ITO is adjustable by changing deposition conditions which make it morelikely to tune the peak position of infrared absorption, thus it is suitable to construct atunable infrared detector;(3) Vanadium oxide with high TCR is deposited by ion beam reactive sputtering and theprocessing factors to influence the growth of vanadium oxide thin film are investigated.(4) For infrared gas sensor application, dual-detection-element chips with verticalconduction structure is designed and fabricated. Breakthroughs are made in developingmultilayer film preparation and ICP etching of silicon for thermal isolation cavity formation. In the end the dual-detection-element chips for gas sensor are successfully implemented andtested.