Study On Pyroelectric Infrared Detector Based On Lithium Tantalate

In recent years, pyroelectric infrared detectors based on lithium tantalate(LiTaO3,a crystalline solid) were adopted in space exploration instead of thermistor infrared detector, because they have such advantages as strong radioresistance, good environmental adaptability, high sensitivity, good consistency of production, etc.So far, researches on lithium tantalate pyroelectronic infrared detectors have been widely carried out in the world. While domestic researches are comparatively rare due to the immature structure design of detector and the lack of researches on sensitive materials, such as the fabrication and reduction of lithium tantalate sensitive material.In this thesis, the working principle of pyroelectric infrared detectors has been discussed, and different sensing element alternative materials were analyzed, and lithium tantalate as sensitive material of detectors of various factors have been adopted.And the properties of pyroelectronic detectors in electricity, thermology and mechanics have been researched combined with plenty of simulations and analyses. Additionally,an experiment of reduction of lithium tantalate chip has been conducted, and a 28-um lithium tantalate chip has been obtained. The specific work is as follow:1.Based on the lumped parameter model, three different supporting structures,including two legs, four legs and five legs, have been proposed. By changing the thickness of sensitive material, the voltage response, noise and detectivity of the pyroelectronic detectors under different supporting structure have been studied, which provide a foundation for selection of sensitive material parameter and structural optimization of instruments.2.Based on the software of finite element analysis, the simulations aiming at the thermal and mechanical properties of several pyroelectronic detectors have been done,and the influence of on the mechanical and thermal properties of pyroelectric detectors have been analyzed. Taking all those affecting factors into account, a 20-um material thickness was preferable and the five legs structure was chosen.3.Based on the discussion of the properties in electricity, thermology and mechanism, reduction of lithium tantalate chip have been done. By improving experiment methods and processing steps, a preferable lithium tantalate wafer is obtained.