| Summary: | 碩士 === 長庚大學 === 電子工程學研究所 === 96 === Since Bergveld reported on ion sensitive field effect transistors (ISFETs) for measuring ion concentrations in solutions, various kinds of chemical sensors have been developed. The commonly accepted model to account for the pH sensitivity of the ISFET is the site-dissociation model, which was firstly proposed by Yates et al. Recently, high-k dielectric materials, such as Al2O3, Ta2O5, TiO2, WO3, and ZrO2 were proposed as hydrogen ion sensing membrane for pH-ISFET to replace Si3N4 membrane because of their high sensitivity performance.
In this thesis, samarium oxide dielectric grown using reactive RF-sputtering was investigated as sensing membrane of pH-EIS structure. We focus on the influence of different gas ratios of O2 : Ar and annealing temperatures to optimize the characteristic of Sm sensing membrane. By physical and electrical analysis, we found the optimum process condition of the gas ratio and different annealing temperature. It exhibited a larger sensitivity, lower drift rate, and smaller hysteresis. Additionally, we combine an enzymatic layer to become a enzymatic film/Sm2O3 sensing membrane/p-Si EIS structure for urea sensor application and we hope it can be extended to bio-sensor application.
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