| Summary: | 碩士 === 長庚大學 === 電子工程學系 === 98 === Since Bergveld reported on ion sensitive field effect transistors (ISFETs) for measuring ion concentrations in solutions, recently the ISFET structure has become more important in medical and environmental measurement applications because it has many advantages such as: small size, high-speed response, easy to operate and having the compatible fabrication technology as CMOS devices and various kinds of chemical sensors have been developed. 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, Dy2O3, DyTixOy and TmTixOy dielectric grown using reactive RF sputtering was investigated as sensing membrane of pH-EIS structure. We found the optimum condition was that the annealing temperature was 900°С. It exhibited a larger sensitivity, lower drift rate, and smaller hysteresis width. Additionally, in order to avoid the generation of hydration layer of the gate insulator and reduce the formation of Dy-silicate, we deposited Ti on Dy2O3 sensing membranes and all samples were rapid thermal annealed (RTA) in O2 to form DyTixOy dielectric films. We found that Ti-doping exhibits better sensing characteristics.
|
|---|
