根據2003美國半導體技術藍圖，西元2006年時MOSFET的閘極氧化層氮氧化物在等效氧化層厚度低於2 nm時將因穿隧效應造成閘極漏電流過大，而導致元件無法操作，因此利用高介電係數材料替代氮氧化物作為閘極氧化層可增加厚度進而降低漏電流成為解決此問題的途徑。
鈦矽氧化膜具有高介電係數、低漏電流、與矽基板介面良好等特性，可應用在矽製程中電晶體的閘極氧化層與記憶體DRAM的介電層。此外，先前的研究指出，鋇的摻雜可以提高薄膜的介電係數。所以，本實驗發展出一種新的薄膜材料稱為鋇摻雜之鈦矽氧化膜。藉由各種特性量測，發現該薄膜具有高介電係數、低漏電流等特性，相較於鈦矽氧化膜在介電方面有更高的應用價值。
本實驗主旨在研究以鋇摻雜之鈦矽氧化膜作為高介電係數材料的物性、化性及電性之表現。利用液相沉積法(LPD)在p-type (100)之矽基板上成長鋇摻雜之鈦矽氧化膜，其過程簡單、成本低廉、而且成長溫度低(40°C)，因此值得廣泛研究和發展。對於物性與化性方面，我們利用掃描式電子顯微鏡(SEM)、反射式光譜儀、二次離子質譜儀(SIMS)、傅立葉紅外線光譜儀(FTIR)與X光繞射儀(XRD)分析，並製作MOS之電容結構以量測其介電特性，並針對鋇摻雜之鈦矽氧化膜之漏電流密度與介電常數等與製程參數之關係加以研究探討。
在本實驗中，以液相沉積法成長鋇摻雜之鈦矽氧化膜在經由氧氣熱退火後，其等效二氧化矽厚度為1.27 nm（介電係數約為22.3），在5 MV/cm電場強度下漏電流密度為2.6 × 10-6 A/cm2 。由本實驗結果顯示,鋇摻雜鈦矽氧化膜於介電應用上具有高發展性。

The area of advanced gate dielectrics has gained considerable attention recently because semiconductor technology roadmaps predict for less than 2 nm equivalent oxide thickness (EOT) for next 10 years, and there are significant leakage current and reliability concerns for oxy-nitride in this regime. So it’s an important business to use alternate high-k dielectrics instead of oxy-nitride.
Titanium silicon oxide shows a low leakage current with a high dielectric constant for dielectric applications. Besides, barium doping can create additional oxygen vacancies that can enhance dielectric constant. In this study, we prepared barium doped titanium silicon by liquid phase deposition which is a novel material considered to have intermediate properties of silicon dioxide and titanium dioxide. From several characteristic measurements, we found that barium doped titanium silicon oxide with exhibiting higher dielectric constant, low leakage current and well interface state which is very promising candidates to instead of titanium silicon oxide.
The physical and chemical properties of barium doped titanium silicon oxide films by means of several measuring instruments, including Fourier transform infrared spectrometer (FTIR), secondary ion spectrometer (SIMS), and X-Ray diffractometer (XRD). An Al / Ba doped titanium silicon oxide / Si metal-oxide-semiconductor (MOS) capacitor structure was used for the electrical measurements.
The static dielectric constant of the O2-annealed barium doped titanium silicon oxide film can reach about 22.3. In addition, it has well leakage current density of 2.6 × 10-6 A/cm2 at 5 MV/cm with the equivalent oxide thickness 1.27 nm (optical thickness of 7.3 nm). It has high potential for dielectric applications.

1.INTRODUCTION.............................................1
1-1 Direct Tunneling Effect of Oxide Layer.................1
1-2 Logic Technology Requirements..........................2
1-3 High Dielectric Constant Materials.....................4
1-4 Advantages of Liquid Phase Deposition..................5
1-5 Motivation.............................................6

2.EXPERIMENTS..............................................8
2-1 Deposition System......................................8
2-2 Cleaning of Silicon Substrate.........................9
2-3 Preparation of Deposition Solution....................10
2-4 Film Deposition.......................................11
2-5 Characteristics.......................................12
2-5-1 Physical Properties.................................12
2-5-2 Chemical Properties.................................13
2-5-3 Electrical Properties...............................13

3.RESULTS AND DISCUSSION.................................16
3-1 Chemical Equilibrium of Ba Doped LPD-TixSi(1-x)Oy Films.....................................................17
3-2 Physical Properties of As-deposited Ba Doped TixSi(1-x)Oy Films..................................................18
3-2-1 Structure of Ba doped TixSi(1-x)Oy Film.............18
3-2-2 Deposition Rate and Refractive Index as a Function of Ba(NO3)2 Molarity in Deposition Solution..............19
3-2-3 SEM Cross-sectional View and Top View of Ba Doped TixSi(1-x)Oy Film on Silicon Substrate....................19
3-3 Chemical Properties of As-deposited Ba Doped TixSi(1-x)Oy Films..................................................20
3-3-1 SIMS Depth Profile of Ba Doped TixSi(1-x)Oy Film....20
3-3-2 FTIR Spectra of Ba Doped TixSi(1-x)Oy Films.........21
3-4 Electrical Properties of As-deposited Ba Doped TixSi(1-x)Oy Films................................................21
3-4-1 Current-Voltage (I-V) Measurement...................22
3-4-2 Capacitance-Voltage (C-V) Measurement...............22
3-5 Characteristics of Post-annealed Ba Doped TixSi(1-x)Oy Film......................................................24
3-5-1 X-ray Diffraction Pattern of Ba Doped TixSi(1-x)Oy Films by Annealing in O2 Ambient..........................25
3-5-2 FTIR Spectra of As-deposited and Post-annealed Ba Doped TixSi(1-x)Oy Films..................................25
3-5-3 Thicknesses of As-deposited and Post-annealed Ba Doped TixSi(1-x)Oy Films..................................25
3-5-4 Improvement of Electrical Properties by Annealing...26
3-6 Characteristics of Thin Ba Doped TixSi(1-x)Oy Film....29
3-6-1 X-ray Diffraction and FTIR Analysis of Thin Ba Doped TixSi(1-x)Oy Films........................................29
3-6-2 Electrical Properties of Thin Ba Doped TixSi(1-x)Oy Films by Annealing in N2 Ambient..........................30
3-6-3 Electrical Properties of Thin Ba Doped TixSi(1-x)Oy Films by Annealing in N2O Ambient.........................31
3-6-4 Electrical Properties of Thin Ba Doped TixSi(1-x)Oy Films by Annealing in O2 Ambient..........................32
3-6-5 Ba Doped TixSi(1-x)Oy Films by O2-Annealed at 500, 600 and 700 ºC (2 min deposited).........................33
3-6-6 Ba Doped TixSi(1-x)Oy Films by O2-Annealed at 500, 600 and 700 ºC (3 min deposited).........................35

4.CONCLUSIONS.............................................37

FIGURES................................................39~76
TABLES.................................................77~78
REFERENCES.............................................79~82

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