離子場效電晶體(Ion-sensitive field effect transistor, ISFET)相較於傳統離子感測電極所沒有的，係具有尺寸小、響應快及可與標準IC製程相容等優點。ISFET主要結構類似於MOSFET，其差異在於MOSFET之金屬閘極被參考電極/電解液/絕緣層(離子感測膜)所取代，且元件直接置於酸、鹼緩衝溶液中，使得感測膜表面產生電位變化，藉此電位變化，可量測出溶液中之氫離子或其他離子濃度。
本論文係以溶膠-凝膠(Sol-gel)法，製備非晶形鈦酸鋇(a-BaTiO3)薄膜，作為H+離子場效電晶體之閘極感測層。首先，將調配鈦酸鋇初始溶液濃度固定為0.42M，進行製備鈦酸鋇薄膜，披覆厚度120~360nm之間鈦酸鋇薄膜於SiO2(1000Å)/p-Si(100)基板上，且進行350~850℃燒結溫度，以形成MIS與EIS薄膜結構。
利用不同pH值緩衝溶液(pH buffer solution)，量測電容-電壓(C-V)特性，利用平能帶電位 (ΔVFB, Flat band voltage)偏移現象，計算a-BaTiO3薄膜於感測度。EIS結果顯示，a-BaTiO3薄膜燒結溫度3500C時，可獲得最佳感測度59.02 mV/pH及線性度0.9991之感測特性，BaTiO3薄膜燒結溫度350~550℃呈現非晶型態，在測試酸、鹼範圍pH 2-12溶液時，呈現整體感測度為40-59 mV/pH。
此外，進行ISFET簡化元件製作流程部分，製程使用光罩數目由原本四道光罩，減為二道程序；製程步驟亦由原來16道步驟減少為10道，已達節約成本之效益。A-BaTiO3 gated ISFET，線性區以定電壓、電流(VDS=0.2 V與IDS=30 μA)條件下，進行感測度量測，感測度為38~48.76 mV/pH。在飽和區工作，其電壓設定為VGS=3 V與VDS=3.5 V，電流感測度表現為-11~-23 μA/pH，線性度為0.997。由C-V與I-V特性表現判斷，鈦酸鋇可實現作為氫離子感測之薄膜材料。

Ion-sensitive field effect transistors (ISFET's) have many advantages than the conventional ion selective electrodes. There exhibt the advantages of small size, fast response and compatible with conventional IC technologies. The general structure of ISFET is the same as that of MOSFET. However, the main difference is that the metal gate in MOSFET is replaced by reference electrode/electrolyte/sensing insulator structure in ISFET. The insulator surface will suffer the change of potential as the sample is immersed into electrolyte, by which, we can measure the pH or other ionic concentration.
Amorphous barium titanate (a-BaTiO3) thin film as the pH-sensing layer of the ion-sensitive field-effect transistor is prepared by a sol-gel technique. The stock solution in a concentration about 0.42M is obtained. The barium titanate thin films are deposited on SiO2(1000Å)/p-Si substrates, and the EIS structure is frabricated. The fabrication parameters of BaTiO3 thin films are made up of the thickness of 120-360 nm and the firing temperature between 350℃ and 850℃.
The flat-band voltage(ΔVBF) is shifted by C-V measurement. The pH sensitivity is on the downside because the thin films thickness and defect increase. The results reveal the MIS C-V curve. The optimum conditions are found that the annealing temperature is about 350℃, and the sensitivity of about 59.02 mV/pH with regression of 0.9991. The pH response of 40-59 mV/pH in the range of pH 2-12 exists when the a-BaTiO3 thin film with thickness of about 120-360nm at the firing temperature between 350℃ and 550℃are prepared.
To decrease the fabrication cost, so the numbers of mask and fabrication steps should be minimized, which are reduced to two from four and 10 from 16 steps. Two masks were used to accomplish a-BaTiO3 gated ISFET. I-V curve shows that the a-BaTiO3 gated ISFET exhibits pH responses of about 38 ~48.7 mV/pH in the linear region(IDS=30 μA and VDS＝0.2 V), and -11~-24.8 μA/pH in the satiation region(VGS=3 V and VDS＝3.5 V), and the regression of above 0.997 was achieved. Both of C-V and I-V curves revealed the BaTiO3 thin films could be used in the ISFET gate.

摘 要 I
ABSTRACT III
目　錄 V
圖目錄 IX
表目錄 XII
第一章　前　言 1
第二章　溶膠-凝膠製備薄膜與分析 3
2.1　溶膠－凝膠法 3
2.1.1　初始原料選配依據 3
2.1.2　初始溶液分析 4
2.1.3　薄膜製作 4
2.1.4　低溫焦化處理 5
2.1.5　高溫結晶熱處理 5
2.2　薄膜特性分析 5
2.2.1　X光繞射分析 5
2.2.2 掃瞄式電子顯微鏡分析 6
2.3 薄膜電性探討 6
2.3.1 MIS與EIS結構特性探討 7
2.3.2表面鍵結分離模型(site-dissociation model) 10
2.3.3 EIS結構之理論特性的探討 12
2.4 ISFET元件之探討 13
2.4.1 ISFET與MOSFET之相關特性 13
2.4.2 ISFET元件之吸附特性 14
2.4.3 ISFET元件電流特性 15
第三章 BaTiO3 gated ISFET製備 18
3.1 Sol-gel初始溶液的研製與調配 18
3.1.1 實驗藥品 18
3.2 薄膜製作 20
3.2.1 薄膜製作 21
3.2.2 薄膜熱處理 21
3.2.3 膜厚與表面結晶狀態 22
3.3 BaTiO3之MIS與EIS結構製備 24
3.3.1 MIS、EIS結構之C-V量測建立 25
3.4 BaTiO3之ISFET元件的備製 25
3.4.1元件光罩 25
3.4.2 BaTiO3 gated ISFET元件製程 25
3.4.3 BaTiO3 gated ISFET特殊製程說明 27
3.4.4 I-V量測系統之建立 28
第四章　BaTiO3 gated ISFET結果與討論 30
4.1 初始溶液調配 30
4.1.1 初始原料溶解 30
4.1.2 初始溶液析出問題 30
4.2 MIS與EIS薄膜性質分析 31
4.2.1 MIS C-V曲線與厚度關係 31
4.2.2 EIS 厚度與感測度關係 32
4.2.3 EIS 燒結溫度與感測度分析 33
4.3 BaTiO3 gated ISFET之分析與討論 34
4.3.1 ISFET I-V特性曲線 34
4.3.2 ISFET之氧化層改善 34
4.3.3 IDS-VDS量測 35
4.3.4 IDS-VGS量測 37
4.3.5 BaTiO3與PbTiO3 ISFET I-V比較 38
第五章　結　論 39
參考文獻 41

[1] P. Bergveld, Development of an ion-sensitive solid-state device for neurophysiological measurements, IEEE Transactions on Bio-Medical Engineering, (1970) p.p.70-71.
[2] L. Bousse, S. Mostarshed, B. van der Schoot and N. F. de Rooij, Comparison of the hysteresis of Ta2O5 and Si3N4 pH-sensing insulators, Sensors and Actuators B, 17 (1994) p.p.157-164.
[3] D. L. Harame, L. J. Bousse, J. D. Shott and J. D. Meindl, Ion-sensing devices with silicon nitride and borosilicate glass insulators, IEEE Trans. Electron Devices, vol. ED-34 (1987) p.p.1700-1707.
[4] M. N. Niu, X. F. Ding and Q. Y. Tong, Effect of two types of surface sites on the characteristics of Si3N4-gate pH-ISFETs, Sensors and Actuators, B 37 (1996) p.p.13-17.
[5] 廖宏逵，氧化錫感測器應用在離子感測場效電晶體元件之研究，中原大學，博士論文(1999)。
[6] 江榮隆，非晶形三氧化鎢場效型離子感測元件之研究，國立雲林技術學院，碩士論文(1997)。
[7] 盧俊德，以溶膠–凝膠法製備鈦酸鉛薄膜作為氫離子場效電晶體感測器之研究，碩士論文(2001)。
[8] 詹珮甄，以鈦酸鉛鎂薄膜作為場效型氫離子感測元件之研究，中山大學碩士論文(2001)。
[9] 蘇仁福，以溶膠-凝膠法製備鈦酸鉛鑭薄膜作為氫離子場效電晶體感測器之研究，中山大學碩士論文(2002)。
[10] P. Gimmel, B. Gompf, D. Schmeisser, H.D. Wiemhofer, W. Gopel and M. Klein, Ta2O5-gates of pH-sensitive devices: comparative spectroscopic and electrical studies, Sensors and Actuators, 17 (1989) p.p.195-202.
[11] D. E. Yates, S. Levine and T. W. Healy, Site-binding model of the electrical double layer at the oxide/water interface, J. Chem. Soc. Faraday Trans. I, 70 (1974) p.p.1807-1818.
[12] E.K. Evangelou, N. Konofaos, M.R. Craven, W.M. Cranton, C.B. Thomas, Characterisation of the BaTiO3 p-Si interface and applications, Applied Surface Science 166(2000) p.p.504–507
[13] Q.X. Jia, L.H. Chang, W.A. Anderson, Low leakage current BaTiO3 thin film capacitors using a multilayer construction, Thin Solid Films 259 (1995) p.p.264-269
[14] L.H. Chang , W.A. Anderson, Stability of BaTiO3 thin films on Si, Applied Surface Science 92 (1996) p.p.52-56
[15] J.J XU, A. S. sheikh, R. W vest, High K BaTiO3 films from metalloorgangic precursor, IEEE transactions on ultrasonics, ferroelectrics, and frequency control, vol. 36, NO 3 (1989)P307-
[16] M. Manso-Silvan , L. Fuentes-Cobas , R.J. Martın-Palma , M. Hernandez-Velez , J.M. Martınez Duart, BaTiO3 thin films obtained by sol–gel spin coating, Surface and Coatings Technology 151 –152 (2002) p.p.118–121
[17] H.X. Zhang, C.H. Kam , Y. Zhou, X.Q. Han, Y.L. Lam, Y.C. Chan, K. Pita, Optical and electrical properties of sol–gel derived BaTiO3 films on ITO coated glass, Materials Chemistry and Physics 63 (2000) p.p.174–177
[18] O.A Harizanov, Sol-gel BaTiO3 from a peptized solution, Materials Letters 34 (1988) p.p.232-236
[19] 蘇毅、楊亞玲、李國斌 鈦酸鋇陶瓷粉體的合成技術，化工進展，2002年第二期 p.p.51
[20] Chen-Feng Kao, Wein-Duo Yang,Preparation of Barium Strontium Titanate Powder from Citrate Precursor, Applied organometallic chemistry, 13, (1999)p.p.338-397
[21] 江旭禎,Chemistry(The Chinese chem. soc.,Taiwan China) mar., Vol.48, No.1 (1990) p.p.50-57.
[22] D. R. Ulrich, Sol-Gel Processing, Chemtech, (1986) p.p.795-797.
[23] 施敏著， 張俊彥譯， 半導體元件之物理與技術， 儒林，(1990) p.p.272~276。
[24] D.E Yate, S. Levine and T.W. Healy, Site-binding model of the electrical double layer at the oxide/water interface. J.Chem. Soc Faraday Trans. I, 70 (1974) 1807-1818。
[25] 武世香､虞 惇､王貴華，化學量感測器，感測器技術，第3期 (1990) p.p.55-60。
[26] Wong, Anthony Sai-Hung, Theoretical and experimental studies of CVD aluminum oxide as A pH sensitive dielectric for the back contacts ISFET, ph.D. Dissertation, Department of Biomedical Engineering, Case Western Reserve University, May (1985)
[27] 武世香、虞惇、王貴華，化學量傳感器 感測器技術，第3期 (1990) p.p.55~60。
[28] 王澄霞、陳朝棟，基礎化學(一)東大圖書公司(1986)
[29] 李明智，以溶膠-凝膠法製備二氧化鈦應用於延式閘極氫離子感測場效電晶體，大業大學，碩士班論文。(2005)p.p.11~13
[30] 唐國洪、陳德英，東南大學，電子器件，第18卷第二期(1995年6月)
[31] 蕭清南，非晶形矽氫與氧化鉭酸鹼離子感測場效電晶體之溫度效應、遲滯和時漂的模擬與研究，國立雲林技術學院，碩士論文(1998)。
[32] 莊達仁，VLSI 製造技術，高立，(1995)p.p.477-491及p.p.496-498。
[33] John A, Hooton, and J. Merz, Etch patterns and ferroelectric domains in BaTiO3 single crystals, physical review(1954) p.p409~413
[34] 陳伯宜、魏琮修、陳建瑞， 以溶膠凝膠法製備鈦酸鋇薄膜做為氫離子場效電晶體之研究，真空技術 19卷2期
[35] R.E.G van Hal, P.Berveld, J.F.J Engbersen, D .N. Reinhout, Characterization and testing of polymer-oxide adhesion to improve the. packaging reliability of ISFETs, sensors and actuators B 23(1995)p.p.17-26