| Summary: | 碩士 === 長庚大學 === 電子工程研究所 === 94 === ISFET, one of the most important bio-devices, has been investigated extensively in recent year because of some good advantages than traditional ion electrode, such as, small device size, short response time, firm and resistant to impacts, fewer test solution and compatible with CMOS VLSI technology. As the size of silicon dioxide-based transistors continues to be sized down in order to obtain good performance and faster devices, the high-k dielectric material was used to replace silicon dioxide to overcome leakage current issue of MOSFET. Above mention, hafnium dioxide as promising high-k material to replace silicon dioxide was used as sensing membrane of ISFET in order to compatible with CMOS fabrication process in the future.
In this work, we used hafnium dioxide as sensing insulator of EIS (electrolyte-insulator-Si substrate) structure which is convenient to fabricate without considering source/drain effect to investigate the sensing properties. The experiments were divided into three parts: first, the nitrided effect on hafnium dioxide sensing properties was studied; second, we proposed a new single sensing layer structure without buffer oxide and investigate the limitation on hafnium dioxide thickness. Then, we used RTA (rapid thermal annealing) method to improve the sensing properties. Finally, we proposed the sensing mechanism model of thin hafnium dioxide and the improvement by RTA; Third, the fluorinated effect on thin hafnium dioxide of new single sensing layer structure was studied.
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