摘要
自從Bergveld提出可量測溶液中離子濃度的離子感測場效電晶體(ISFET)後，各式各樣的化學感測器如雨後春筍般發展。近年來，高介電質材料，例如五氧化二鉭、三氧化二鋁、二氧化鈦、三氧化鎢和二氧化鋯..等材料相繼應用於ISFET離子感測膜的製備上，相對於傳統氮化矽與二氧化矽感測膜，它們也有較高的感測特性表現。
本篇論文我們探討以射頻濺渡方式沉積出來的鐠釔氧化層與銩氧化層作為EIS的離子感測膜。我們將使用不同氬氣與氧氣流量比例以及不同的回火溫度沉積薄膜，並找出最合適之製程條件。經由物性與電性分析，我們發現特定的回火溫度與氧氣與氬氣的比例所沉積出來的鐠釔氧化層與丟氧化層薄膜，會出現較高的感測度與較低的時漂現象與遲滯現象。另外， 我們將做更進一步的研究，在特性較出色的感測膜上面結合了一層酵素感測膜 ,形成ㄧ個酵素膜/鐠釔氧化層感測膜/p型矽基板的感測器結構 ,藉由這個結構來進行尿素感測 ,希望未來在生物感測器方面更加延伸應用。

Abstract

Since Bergveld brought up first ion sensitive field effect transistors (ISFETs) for investigating ion concentrations in solutions, various kinds of chemical sensors have been developed. Recently, high-k dielectric materials, such as Ta2O5, Al2O3, TiO2, WO3, and ZrO2 were investigated as hydrogen ion sensing membrane for pH-ISFET to substitute for Si3N4 and SiO2 membranes because of their high sensing performance.
In this research, PrYxOy and Tm2O3 dielectric layer grown using reactive RF sputtering was investigated as sensing membrane of pH-EIS structure. We investigated specifically on the influence of different gas flow ratios of Ar : O2 and annealing temperatures to find the optimum condition of PrYxOy and Tm2O3 and sensing membrane. According to the physical and electrical analysis, we found the optimum process condition of the different gas ratio and annealing temperature. It exhibited a higher sensitivity, lower drift rate, and smaller hysteresis. In addition, we made a further research on combining thin enzyme film to form a enzymatic film/ PrYxOy sensing membrane/p-Si EIS structure for urea sensor application and we hope it can be extendtively used to bio-sensor application.

Contents
Acknowledgment………………………….................……………………………...i
Abstract (in Chinese)…………………………................…………………………...ii
Abstract (in English)………………….................………………………………...iii
Contents…………………………………...............…………………………………iv
Table & Figure Captions……………………………................……………….…....vi
Chapter 1 Introduction
1-1 General back ground .……………………................….…….….……1
1-2 Electrochemical device with EIS structure …….…...................….……2
1-3 General concept of biosensor …………..............……..……...….……..3
1-4 Motivations & Objectives………………...............…….........................4
1-5 Scope and Structure of the thesis.............................................................6
Chapter 2 Theory Description
2-1 Introduction………………………………….............…………………...10
2-2 Site binding model...............................................................................…...10
2-3 EIS structure...............................................................................................14
2-4 The concept of ISFET.................................................................................15
Chapter 3 Physical and Electrical Properties of PrYxOy/Si EIS structure
3-1 Introduction of thin film…………….............………………………........20
3-1-1 Yttrium oxide gate dielectric...............................................................20
3-1-2 Praseodymium oxide gate dielectric….................…………….…..20
3-1-3 PrYxOy oxide gate dielectric……………............….…..……………21
3-1-4 RF Sputtering……………………………………….............……..21
3-2 Experiments………………………………………...........………………22
3-3 Analysis of PrYxOy oxide sensing membranes……............………...........23
3-3-1 Physical analysis.................................................................................23
3-3-2 Atomic force microscopy (AFM) results of PrYxOy sensing membranes.........................................................................................24
3.3.3 Secondary Ion Mass Spectroscopy (SIMS) results…................……..24
3-4 Electrical analysis.......................................................................................25
3-4-1 The C-V curve of PrYxOy sensing membrane...................................25
3-4-2 Sensitivity of PrYxOy sensing membrane...………..........................25
3-4-3 Drift of PrYxOy -EISs.......……………….........................................26
3-4-4 Hysteresis phenomenon of pH sensing.............................................27
Chapter 4 Physical and Electrical Properties of Tm2O3/Si EIS structure
4-1 Introduction……………………………………...........…………….........39
4-2 Experiments………………………..........…………………….…..….… 40
4-2-1 Thulium oxide.....................................................................................40
4.3 Physical analysis.........................................................................................41
4.3.1 XRD analysis of Tm2O3 thin film.................................................…...41
4.3.2 Tm oxide film analysis by X-ray photoelectron
spectroscopy (XPS)………………………..........………………..…41
4.4 Electrical analysis……………………………...........…………….……42
4.4.1 Sensitivity of Tm2O3 sensing membrane…………..........……..…….42
4.4.2 Drift of PrYxOy –EISs……………………….…..........….…………..43
4.4.3 Hysteresis phenomenon of pH sensing…………............……….....44
Chapter 5 Application of PrYxOy-EIS structure to urea sensor
5.1 Introduction......................................................................................….......57
5.2 experiment of urea sensor……………………….........…………..………58
5.2.1 Materials…………………………………….........………………..58
5.2.2 The process of enzyme fixing for urea sensor……................…….…58
5.3 Results and discussion……………………………...........……………59
Chapter 6 Conclusions and Future Works
6.1 Conclusions………………………………........………………………….62
6.2 Future works…………………………………………...........……….…...63










Figure Caption
Chapter 1
Table 1. Type of electrochemical for classified type of measurements, with corresponding analytes to be measured Bergveld and Thevenot , 1993 [1] .
Fig.1-1 Schematic ion-sensitive field effect transistor (ISFET) diagram (Source: TIMA).
Fig. 1-2 The illustration of an electrolyte-insulator-semiconductor (cross-sectional view).
Fig. 1-3 A schematic representation of a biosensor.

Chapter 2
Fig. 2-1 Schematic representation of the site binding model.
Fig. 2-2 Experimental results of the surface potential ( ) on the SiO2 surface, using the theoretical parameters pHpzc=2.2, β=0.14, pKa=5.7, pKb=1.3, Ns=5×1014cm-2 and CDL=20uF/cm-2.
Fig. 2-3 Experimental results of the threshold voltage variation of the Al2O3 gate ISFET, using the theoretical parameters pHpzc=8, β=4.8, pKa=10, pKb=-6, Ns=8×1014cm-2 and CDL=20uF/cm-2.
Fig. 2-4 Typical C-V curves for electrolyte-SiO2-Si EIS structure. Silicon dioxide thickness is 560Å on a (100) 10Ω-cm p-type.
Fig.2-5 Basic and multi-phase diagram.


Chapter 3
Fig. 3-1 Typical RF sputtering system.
Table. 3-1 Deposition conditions of PrYxOy thin film using RF sputtering system.
Fig. 3-2 EIS structure with PrYxOy sensing membrane.
Fig. 3-3 Flow chart of PrYxOy EIS process.
Fig. 3-4 AFM results of (Ar:O2 = 15:15 ,at as-dep).
Fig. 3-5 AFM results of (Ar:O2 = 15:15 , RTA at 700°C).
Fig. 3-6 AFM results of (Ar:O2 = 15:15 , RTA at 800°C).
Fig. 3-7 AFM results of (Ar:O2 = 15:15 , RTA at 900°C).
Fig. 3-8 The RMS for different RTA conditions at Ar:O2 = 15:15.
Fig. 3-9 SIMS results of PrYxOy EIS process.
Fig. 3-10 C-V curves of PrYxOy EIS RTA at 800°C for all standard pH buffer solutions.
Fig. 3-11 Extracted response voltages for varied pH with fitting the value of sensitivity and linearity at an annealing condition of 800°C.
Fig. 3-12 Sensitivity of PrYxOy films at different temperature of RTA temperature in Ar/O2 of 15:15 and 20:10.
Fig. 3-13 Linearity of PrYxOy films at different temperature of RTA temperature in Ar/O2 of 15:15 and 20:10.
Fig. 3-14 The drift of PrYxOy /Si-EIS at 800°C with the Ar/O2 ratio of 20:10.
Fig. 3-15 Sensitivity and drift of PrYxOy/Si-EIS at varied annealing temperature with the Ar/O2 ratio of 15:15.
Fig. 3-16 Sensitivity and drift of PrYxOy/Si-EIS at varied annealing temperature with the Ar/O2 ratio of 20:10.
Fig. 3-17 Hysteresis of PrYxOy /Si-EIS at an annealing condition of 800°C was tested in the cycle of pH 7→4→7→10→7.
Fig. 3-18 Hysteresis of PrYxOy sensing membrane annealed at various RTA conditions and Ar/O2 ratio by the cycle of pH 7→4→7→10→7.

Chapter 4
Table. 4-1 Deposition conditions of Tm2O3 thin film using RF sputtering system.
Fig. 4-1 EIS structure with Tm2O3 sensing membrane.
Fig. 4-2 The flow chart of Tm2O3 EIS process.
Fig. 4-3 XRD results of Tm2O3 thin film (Ar:O2 = 20:10) at different RTA temperature.
Fig. 4-4 XRD results of Tm2O3 thin film (Ar:O2 = 15:15) at different RTA temperature.
Fig. 4-5 XRD results of Tm2O3 thin film (Ar:O2 = 10:20) at different RTA temperature.
Fig. 4-6 X-ray photoelectron spectroscopy of Tm2O3 film, Ar:O2 (20:10) , Tm 4d region for different annealing temperature.
Fig. 4-7 X-ray photoelectron spectroscopy of Tm2O3 film, Ar:O2 (15:15), Tm 4d region for different annealing temperature.
Fig. 4-8 X-ray photoelectron spectroscopy of Tm2O3 film, Ar:O2 (10:20), Tm 4d region for different annealing temperature.
Fig. 4-9 X-ray photoelectron spectroscopy of Tm2O3 film, Ar:O2 (20:10), O 1s region for different annealing temperature.
Fig. 4-10 X-ray photoelectron spectroscopy of Tm2O3 film, Ar:O2 (15:15), O 1s region for different annealing temperature.
Fig. 4-11 X-ray photoelectron spectroscopy of Tm2O3 film, Ar:O2 (10:20), O 1s region for different annealing temperature.
Fig. 4-12 C-V curves of Tm2O3 EIS RTA at 800°C for all standard pH buffer solutions.
Fig. 4-13 Extracted response voltages for varied pH with fitting the value of sensitivity and linearity at an annealing condition of 800°C.
Fig. 4-14 Sensitivity of Tm2O3 films at different temperature of RTA temperature in Ar/O2 of 20:10, 15:15 and 10:20.
Fig. 4-15 Linearity of Tm2O3 films at different temperature of RTA temperature in Ar/O2 of 20:10, 15:15 and 10:20.
Fig. 4-16 Drift of Tm2O3/Si-EIS at varied annealing temperature.
Fig. 4-17 Sensitivity and drift of Tm2O3/Si-EIS at varied annealing temperature with the Ar/O2 ratio of 20:10.
Fig. 4-18 Sensitivity and drift of Tm2O3/Si-EIS at varied annealing temperature with the Ar/O2 ratio of 15:15.
Fig. 4-19 Sensitivity and drift of Tm2O3/Si-EIS at varied annealing temperature with the Ar/O2 ratio of 10:20.
Fig. 4-20 Hysteresis of Tm2O3/Si-EIS at an annealing condition of 800°C was tested in the cycle of pH 7→4→7→10→7.
Fig. 4-21 Hysteresis of Tm2O3 sensing membrane annealed at various RTA conditions and Ar/O2 ratio by the cycle of pH 7→4→7→10→7.
Chapter 5
Table. 5-1 Required materials for urea detection.
Fig. 5-1 The C-V curves of PrYxOy EIS structure for different urea concentration of Ar/O2 = 15:15 with 800℃ annealing.
Fig. 5-2 Sensitivity and linearity of PrYxOy EIS structure for different urea concentration of Ar/O2 = 15:15 with 800℃ annealing.

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