Research On Fabrication And Integration Of LiTaO₃single Crystal Pyroelectric Multi-element Infrared Device

Pyroeletric infrared detector has attracted great research attention in the field of infrared detector due to its advantages of fast response,high responsivity,wide temperature zone,low noise and power consumption.Research shows,LiTaO₃ is the most common used pyroeletric material because of good pyroelectric property,high curie temperature,low dielectric constant.However,LiTaO₃ film grow on Si thermal isolation structure are usually polycrystalline structure and showed degenerated pyroelectric properties.Silicon based thermal isolation structure fabricated by MEMS process was used.This paper proposed a new method of integration of LiTaO₃ bulk and suspend thermal isolation structure by UV adhesive,to solve former problem.Then the structure and fabricate process of pyroelectric detector were designed,performance influenced by fabrication technics and structure of detector have been studied further.Parameters of fabrication technics and structure have been improved and used for the fabrication and measurement of 2×2 multi-element detector.1.LiTaO₃ single crystal/quartz substrate with groove structure of detector was designed.Finite element simulation was used for simulation of detector structure.Integration process of LiTaO₃ single crystal and quartz substrate was found by using UV adhesive bonding.Prototype device was fabricated to confirm structure and integration process of detector.2.Impact of electrode patterning and integration process on detector properties were researched.Method of UV laser etching was used for pattern of electrode.With parameters of 30kHz repetitive frequency,0.15W power,400mm/s marking rate,top and bottom electrode could be patterned by 5 and 4 etching times,respectively.Evenness and thickness of UV adhesive was effected by coating time and speed.Impact on detector properties was researched as well.60s coating time and 5000rpm coating speed?16.27?m UV adhesive layer thickness?were used as optimize parameters for the spin-coating of UV adhesive.3.Quartz substrate with groove was designed to be thermal isolation structure.Finite element simulation was used to research the impact of detector structure on thermal and stress properties.UV laser etching of LiTaO₃ single crystal was researched.Research shows:The larger the air gap area of the thermal insulation structure of the detector is,the better the thermal performance is.7mm×7mm air gap area is selected in combination with mechanical simulation.UV laser etching of Li TaO₃ single crystal was researched systematically to form laterally thermal isolation structure.Maximum59.2?m etching depth and maximum 0.4mm etching width could be realized on optimize process condition.4.The optimized fabrication and structure are used for the fabrication and measurement of a 2×2 multi-element detector.The maximum R_V can reach1135.241V/W.The maximum D*can reach 2.77×10⁸cm·Hz^1/2/W.