Study On Micro Sturcture And Process Design Of Vanadium Oxide Bolometers

In recent years, thermal imaging techniques based on micromachined uncooled infrared detectors have been paid much attention in the fields of MEMS and optical imaging. In this dissertation, preparation and thermoelectric characterization of vanadium oxide (VOx) material and device have been studied. A novel MEMS-IC integration method based on porous silicon micromachining has been developed, which is used to fabricate resistive bolometers with vanadium oxide (VOx) with nrimarv canahilitv cf thermal ima}ina have heen rencrted fcr the first timeFirstly, high-quality Vanadium oxide thin film with nanostructure was deposited by novel facing targets DC reactive sputtering technique using V metal as target. The effects of SiO2 substrate and Si3N4 substrate on composition of vanadium oxide thin films deposited using direct current facing targets magnetron sputtering at high substrate temperature were investigated.X-ray photoelectron spectroscopy analysis revealed the vanadium oxygen state of the film, which included V2O5,VO2 and a few V2O3 and atomic force microscopy surface morphology indicated a planar and compact film surface. The temperature coefficient of resistance (TCR) and the sheet resistance of VOx are tested and analyzed. It shows that VOx on oxide have higher infrared detective performance than VOx on nitride. The temperature coefficient of resistance (TCR) as-deposited was high up to -3.2%/℃and the sheet resistance was about 14K?/□around room temperature.Secondly, porous silicon (PS) is prepared by electrochemistry etching method to selective growth methods of PS, thermal isolation and mechanical performance of porous silicon on its microstructure is analyzed, which affords a certain thermal and mechanical parameters for the manufacture of Uncooled Infrared Bolometer. Integration approach based on porous silicon sacrificial layer techniques and thermal isolation ability is developed for MEMS integration.Finally, based on theoretical analysis and structure designs, vanadium oxide bolometers layouts and process-flow designs are performed. The process flow using the MEMS-IC integration processes of bolometers with various structures and dimensions are improved.