| Summary: | 碩士 === 國立雲林科技大學 === 電子與資訊工程研究所碩士班 === 91 === In this thesis, the principle of the MOSFET was used for the ISFET. The gate metal of the MOSFET was substituted for the insulator over the SiO2 , which must be sensitive for the H+ and/or OH- in the buffer solution. Reference electrode was used to supply the reference potential for the buffer solution. The threshold voltage (VT) of the ISFET will be shifted in the various pH buffer solutions. Hence, the pH value of the solution can be detected by the ISFET. In this thesis, the sensing films of titanium dioxide (TiO2) deposited by the sputtering deposition method were studied.
There are many unstable factors to affect the applications of the pH-ISFET, especially the temperature, hysteresis and drift effects, which were aimed to study in this thesis. About the TiO2, the three unstable factors would all be studied in our research. Furthermore, qualitative and quantitative analysis of TiO2 thin films are discussed using AFM, XRD, SEM, AES, XPS and so on. Otherwise, we found the sensitivity of the TiO2 gate pH-ISFET can be different in the various conditions of the deposition process. The relationship of the sensitivity versus the deposition conditions was focused on the gas flow, power density and deposition pressure. Finally, the readout circuit would be designed using the standard COMS IC 0.5μm technology, which is achieved for the function of the micro-sensor in the thesis.
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