| Summary: | 碩士 === 國立雲林科技大學 === 電子與資訊工程研究所碩士班 === 90 === In this thesis, the solution of the ferroelectric materials, Barium Strontium Titanate(BaxSr1-xTiO3, BST) were prepared and deposited on SiO2/p-Si(100) substrate as the sensing layer of gas sensor by using sol-gel spin coating technique. In order to increase the sensitivity, the catalyst, Pd, was added in the sensor. The structure of the gas sensor is metal/ferroelectrics thin-film/insulator/semiconductor (MFIS). The current-voltage measurements were made by adding oxygen gas and carbon monoxide (CO) into the testing chamber as sensing gas for sensors processing under different annealed temperature and time. We deploied four kinds of different Barium(Ba) and Strontium(Sr) ratio of the Barium Strontium Titanate(BaxSr1-xTiO3) solutions by sol-gel method, where x is 1, 0.8, 0.7 and 0.5. The experiments were shown that the senseing device wasn’t suitable for long-time annealing . Experimental results clearly show that the BaTiO3 thin film had a optimum voltage shift at 1000 ppm oxygen and carbon monoxide (CO) gas. And the Ba0.7Sr0.3TiO3 thin film only detected oxygen gas that had the good gas sensitivity, so selectivity was optimum. Experimental results show that the response time of the BaTiO3 thin film to gas concentration that was short than others. BST thin films would form perovskite phase after thermal annealing treatment upward 450 ℃ by XRD measurement. AFM measurements BST thin films could decrease the surface roughness under low temperature and short time of thermal annealing treatment, but the surface roughness increase after high temperature of thermal annealing treatment .
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