中文摘要：
近年來，鈦氧化膜被研究來應用在光學元件和電子元件(如波導、DRAM)已有增加的趨勢。鈦氧化物由於具有高介電常數,高折射係數和高化學穩定性，故有希望應用於上述的方面。
由於傳統成長氧化層的方法，如：分子束磊晶(MBE)、化學氣相沉積(CVD) 、sol-gel等均須在高溫沉積或高溫處理，高溫會對元件造成一定程度的傷害。所以我們研究一種新的技術以“液相沉積法(Liquid Phase Deposition-LPD) ”生長氧化鈦薄膜，其過程簡單、成本低廉、而且成長溫度極低(小於100℃)，因此值得廣泛研究和發展。但液相沉積法有一個缺點即是生長速率緩慢.
在過去的研究中,生長速慮緩慢,只有 6Å/min,當初是只以六氟鈦酸和硼酸為主要溶液.為了增加生長速率,我們添加了硝酸到主要溶液當中.另外,我們還研究了添加水,氨水以及氫氧化鋇對於改變溶液中酸鹼值及對氧化膜特性的影響。
對於量測氧化鈦薄膜的電特性和厚度方面，我們是利用電容-電壓曲線(C-V Curve) ，漏電流密度-電場強度曲線(J-E Curve)和反射式光譜儀,可瞭解薄膜的介電常數(εr)、漏電效應並得知平帶電壓偏移(VFB) 、有效電荷密度(Qeff)以及厚度，折射係數。結果,我們得之可以藉由添加硝酸和添加適量的氨水來調變pH值可以增加成長速率，由 6 Å/min 增加到 475 Å/min，電特性也可以改善，介電常數(εr)也增加到 36.03。

In recent years, titanium oxide thin film has been studied extensively for using in optical devices and electronic devices such as waveguide and future ultra-large scale dynamic random access memory (DRAM). Titanium oxide film is very promising candidates for applications with exhibiting higher dielectric constant, high refractive index and high chemical stability.
Liquid phase deposition is a novel method to grow oxide layer. It has the advantage of low-temperature deposition, good step coverage, and selective growth. We use this technology to deposition titanium oxide film instead of the conventional methods of growth titanium oxide film, such as sol-gel, sputtering, LPCVD, APCVD, and PECVD. But low deposition rate is one of the drawbacks drawbacks of LPD process.
In previous study, deposition rate of titanium oxide films was very slow (6Å/min). The mixture of H2TiF6(aq) and H3BO3(aq) was used as the principal solution. In this study, we incorporated HNO3(aq) into the principal solution for enhance the deposition rate. In addition, we study the deposition rate and dielectric constant of titanium oxide films as functions of H2O addition, NH4OH(aq), and Ba(OH)2(aq) concentrations in our principal solution.
We examine electrical characteristics and thickness of the titanium films by capacitance-voltage measurement and Spectroscopic Reflectance. The deposition rate of titanium oxide film increases from 6 Å/min to 475Å/min and the dielectric constant is about 36.1 with adding HNO3 and opportune NH4OH into the principal solution.

CONTENTS
LIST OF FIGURES………………………………………I
ABSTRACT………………………………………………V
1.INTRODUCTION..…………………………………………1
1-1Developments in DRAM………………………………1
1-2High Dielectric Constant Material……………………1
1-3Background of Liquid Phase Deposition (LPD) in Our Labortary………………………………………………2
1-3-1 LPD-SiO2…………………………………………………………………………………2
1-3-2 LPD-SiON and Biased-LPD-SiON …………………………4
1-3-3 LPD-TiO2 and new mechanism of LPD-TiO2 by
incorporating nitric acid……………………………………6
1-4Advantages of LPD Deposition…………………………………8
2.EXPERIMENTS………………………………10
2-1 Deposition System……………………………………10
2-2 Cleaning of Silicon Substrate…………………………11
2-3 Preparation of Deposition Solution……………………12
2-4 Film Deposition………………………………………14
2-5 Fabrication of MOS Structure………………………15
2-6 Characteristics………………………………………16
2-6-1 Physical Properties………………………………………16
2-6-2 Chemical Properties………………………………………16
2-6-3 Electrical Properties………………………………………17
3.RESULTS AND DISCUSSION ………………………19
3-1 Effect of HNO3 and H3BO3…………………………………19
3-1-1 Deposition Rate and Refractive Index as a Function of HNO3 Volume……………………………………………………19
3-1-2 Deposition Rate, Refractive Index and Dielectric Constant as a Function of H3BO3 Molarity……………………………20
3-1-3 Deposition Rate, Refractive Index and Dielectric Constant as a Function of H3BO3 Molarity with Different HNO3 Volume……………………………………………………22
3-1-4 C-V Measurement …………………………………………22
3-1-5 Analyses of FTIR Spectrum ……………………………23
3-1-6 SIMS Depth Profile of Titanium Oxide Films……………23
3-2 Effect of H2O …………………………………………25
3-2-1 Deposition Rate, Refractive Index and Dielectric Constant as a Function of H2O Volume ……………………………25
3-2-2 Analyses of FTIR Spectrum ………………………………26
3-3 Effect of NH4OH………………………………………26
3-3-1 Deposition Rate, Refractive Index and Dielectric Constant as a Function of NH4OH Morality …………………………26
3-3-2 Deposition rate, Refractive Index and Dielectric Constant as a Function of NH4OH Volume …………………………27
3-3-3 Thickness and Refractive Index as a Function of Time.............29
3-3-4 Deposition Rate, Refractive Index and Dielctric Constant as a Function of NH4OH Molarity ……………………29
3-3-5 SIMS Depth Profile of Titanium Oxide Films ………31
3-3-6 C-V Measurement ………………………………………31
3-3-7 J-E Measurement …………………………………………32
3-3-8 Analyses of FTIR Spectrum …………………………32
3-3-9 SEM Photograph of Titanium Oxide Film………………33
3-4 Effect of Ba(OH)2………………………………………33
3-4-1 Deposition rate, Refractive Index and Dielectric Constant as a Function of B1(OH)2 Volume …………………………33
3-4-2 J-E Measurement …………………………………………34
3-4-3 Analyses of FTIR Spectrum ………………………………35
3-5 X-ray Diffraction (XRD) of Titanium Oxide Films Deposition on Silicon Substrate ……………………35
3-6 Relationship Between pH Value and Deposition Solution…………………………………………………..36
4.CONCLUSIONS ………………………………..….37
Reference ……………………………………………78
LIST OF FIGURES
Figure 1. Schematic diagram of liquid phase deposition (LPD) system …39
Figure 2(a). Deposition flowchart for preparing LPD-titanium oxides films …………………………………………………………40
Figure 2(a). Deposition flowchart for preparing LPD-titanium oxides films ……………………………………………………………41
Figure 3. MOS structure fabrication processes ……………………………42
Figure 4. Deposition Rate and Refractive Index as a Function of HNO3 Volume …………………………………………………………43
Figure 5. Deposition Rate and Dielectric Constant as a Function of HNO3 Volume …………………………………………………………44
Figure 6. Deposition Rate and Refractive Index as a Function of H3BO3 Molarity …………………………………………………………45
Figure 7. Deposition Rate and Dielectric Constant as a Function of H3BO3 Molarity …………………………………………………………46
Figure 8. Deposition Rate and Refractive Index as a Function of H3BO3 Molarity …………………………………………………………47
Figure 9. Deposition Rate and Dielectric Constant as a Function of Molarity of H3BO3 …………………………………………………………48
Figure 10. Flat Band Voltage as a Function of H3BO3 Molarity…………49
Figure 11. High Frequency (1MHz) C-V …………………………………50
Figure 12. FTIR Spectrum of Titanium Oxide Film ………………………51
Figure 13. SIMS depth profile of deposited titanium oxide films deposited on silicon substrate …………………………………………………52
Figure 14. Deposition Rate and Refractive Index as a Function of H2O Volume …………………………………………………………53
Figure 15. Deposition Rate and Dielectric Constant as a Function of H2O Volume …………………………………………………………54
Figure 16. TIR Spectrum of Titanium Oxide Film …………………………55
Figure 17. Deposition Rate and Refractive Index as a Function of NH4OH Morality …………………………………………………………56
Figure 18. Deposition Rate and Dielectric Constant as a Function of NH4OH Molarity …………………………………………………………57
Figure 19. Deposition Rate and Refractive Index as a Function of NH4OH Volume …………………………………………………………58
Figure 20. Deposition Rate and Refractive Index as a Function of NH4OH Volume …………………………………………………………59
Figure 21. Thickness and Refractive Index as a Function of Time …………60
Figure 22. Deposition Rate and Refractive Index as a Function of NH4OH Molarity …………………………………………………………61
Figure 23. Deposition Rate and Dielectric Constant as a Function of NH4OH Molarity …………………………………………………………62
Figure 24. SIMS depth profile of titanium oxide film deposited on silicon substrate for process B …………………………………………63
Figure 25. SIMS depth profile of titanium oxide film deposited on silicon substrate for process B …………………………………………64
Figure 26. Flat Band Voltage as a Function of Various NH4OH Molarity…65
Figure 27. High Frequency (1MHz) C-V …………………………………66
Figure 28. J_E Curves as Functions of Various NH4OH Molatity …………67
Figure 29. FTIR Spectrum of Titanium Oxide Film ………………………68
Figure 30. SEM photograph of titanium oxide film deposited on silicon(a) cross-sectional view (b) top view ………………………………69
Figure 31. Deposition Rate and Refractive Index as a Function of Ba(OH)2 Volume …………………………………………………………70
Figure 32. Deposition Rate and Dielectric Constant as a Function of Ba(OH)2 Volume …………………………………………………………71
Figure 33. J-E Curves as Functions of Various Ba(OH)2 Volume …………72
Figure 34. FTIR Spectrum of Titanium Oxide Films ………………………73
Figure 35. X-ray diffraction (XRD) pattern of titanium oxode film deposited on silincon substrate ……………………………………………74
Figure 36. Titanium Concentration versus pH Value ………………………75
Figure 37. Relationship Between pH Value and Deposition Solution ………76
LIST OF TABLE
Table 1. Electronegativity …………………………………………………77
Table 2. Nature of vibrational groups of titanium oxide films ……………77

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