臺灣博碩士論文加值系統

摘 要
本研究之目的乃是以溶膠-凝膠法（sol-gel technique）製備具有高介電常數及低損失因子的介電薄膜於Al2O3基板上，以應用於電容之被動元件領域。
熱分析研究發現，在溶膠-凝膠法製備BST介電薄膜的過程，其先驅溶液內含之有機分子約在450oC可揮發，而在約500oC左右即可得到無中間相且具鈣鈦礦（perovskite）結構之BST薄膜。另外，亦針對薄膜內部之各組成元素，分析其組成之化學態，亦即其組成離子之價數，此結果顯示各元素於薄膜內部之組成價數皆和理論者相同，顯示薄膜內部並沒有中間相或二次相的存在。
為得到結晶化之BST薄膜，必須做一適當溫度的退火，當退火溫度提高時，晶粒尺寸跟著變大，此現象可由X-ray結晶繞射分析及FESEM影像中得到驗證。根據理論說明，在居理溫度附近的介電常數呈現一相對尖峰，因此可調整Sr元素的組成比例以得到，使得在元件操作溫度附近得到較高之介電常數。因為Ba、Sr原子大小的不同，晶格常數也會跟著變化，研究中經由XRD的結果與理論公式的計算，可得到不同成份比例下之BST薄膜的晶格常數。另外，由結果可得知，經由高溫退火後的BST薄膜，其介電常數將會有大幅度的增加。
Al2O3基板已廣泛應用於被動元件領域，但因為Al2O3基板的表面粗糙度遠較Si基板大，因此鍍覆於Al2O3基板上的漏電流將遠較Si基板上者來得大。為減低Al2O3基板上之電容的漏電流，使之可順利應用，實驗設計以Al元素的添加來降低元件之漏電流。結果顯示，Al的添加可有效抑制漏電流的產生，此和其界面的能障與晶粒的減小有極大的相關。

Abstract
The BaxSr1-xTiO3 and Al-doped BST thin films were fabricated on Pt/TaN/SiO2/Si and Al2O3 substrates using sol-gel technique. The structure and thermal decomposition were investigated by means of thermogravimetric/differential thermal analysis (TG/DTA), Fourier transform infrared spectroscopy and X-ray diffractometer (XRD) analysis. The composition and chemical states of elements in BST thin films were characterized using X-ray photoelectron spectroscopy (XPS) technique. The results of thermal decomposition indicated that most of the organics such as acetate and carbonate decomposed below 420oC. The perovskite structure formed above 450oC. The convoluted spectrums of XPS patterns revealed that the chemical states of Ba, Sr, Ti and O are Ba2+, Sr2+, Ti4+ and O2-, respectively. The convoluted Ba photoelectron spectrum showed two different Ba bonding types, the typical BST mode and a relaxation-related mode. The oxygen photoelectron spectrum consisted of the normal perovskite peak and two high energy components which were due to the surface contaminations.
Aluminum was introduced to depress high leakage current due to the surface roughness of Al2O3 substrate. The doped Al substitute Ti-sites of BST perovskite structure. Two possible current transport mechanisms including Schottky emission and Poole-Frenkel emission are employed to explain the current characteristics of BST thin films. The different dominant conduction mechanisms are dependent on the electric field and the surface roughness of the substrates. The barrier heights of Schottky and Poole-Frenkel emission at forward bias are both higher than those at reverse bias, which may be attributed to the different roughness of pre-layers. The Al-doped BST thin films exhibit finer grains on the basis of XRD patterns and FESEM observations and higher potential barrier, thus leakage current is reduced.

Contents
List of TablesIV
Figures CaptionV
AbstractX
Chapter I. Introduction1
Chapter II. Literature Review4
2.1 Thin film dielectrics4
2.1.1 Materials for dielectrics4
2.1.2 High dielectric constant and low dissipation factor material－ (Ba,Sr)TiO34
2.2 Dielectric characteristics10
2.2.1 Polarization and polarization mechanisms10
2.2.2 Dielectric loss14
2.2.3 Characteristic of frequency18
2.3 The parameters in fabrication22
2.3.1 Preparation of BST thin film22
2.3.1.1 Sol-gel processing of films22
2.3.1.2 The gelation process23
2.3.1.3 The effects of thickness of BST thin film25
2.3.2 Influences of substrates27
2.3.2.1 The effects of lattice constant and thermal expansion coefficient27
2.3.2.2 The workfunction and surface roughness of the electrodes31
2.3.3 Post-annealing and grain size effect37
2.3.4 Effect of oxygen/argon ratio43
2.3.5 Effects of doping atoms49
2.4 Applications in High Frequency Region50
Chapter III. Experimental Procedure52
3.1 Preparation of Substrates52
3.1.1 Cleaning52
3.1.2 Silicon Dioxide Layer52
3.1.3 Adhesion Layer53
3.1.4 Bottom Electrode53
3.2 The Preparation of BST Precursor53
3.2.1 Undoped BST Thin Film53
3.2.2 Al-doped BST Thin Film54
3.3 Producing the Dielectric Thin Film55
3.3.1 Spin Coating55
3.3.2 Crystallization of BST Thin Film55
3.4 Analysis and Measurement56
3.4.1 Microstructure and surface morphology56
3.4.2 Phase identification57
3.4.3 Composition Analysis57
3.4.4 Thermal Analysis58
3.5 Measurements of Electrical and Dielectric Characteristics.59
3.5.1 Top Electrode59
3.5.2 Electrical and Dielectric properties59
Chapter IV. Results and Discussion64
4.1 Thermal Analysis64
4.1.1 TG/DTA64
4.1.2 FTIR Analysis64
4.2 Composition and Quantitative Analysis71
4.2.1 XPS (ESCA) Analysis71
4.2.1.1 Peak Deconvolution73
4.2.1.2 Quantitative Analysis75
4.2.2 SIMS analysis82
4.3 Microstructures of BST thin films84
4.3.1 XRD Analysis84
4.3.2 Micromorphology of BST thin films94
4.4 Electrical and Dielectric Characteristics97
4.4.1 Leakage Current97
4.4.2 Conduction Mechanisms99
4.4.3 Electrical Characteristics of Al-doped Thin Films106
4.4.4 Capacitance and Dielectric Constant106
Chapter V. Conclusions109
References111
Tables List
Table I. The lattice constants and thermal expansion coefficients of BST, MgO and LaO29
Table II. The results of semi-quantitative analysis of Ba0.65Sr0.35TiO3 thin films from XPS spectra81
Table III. Grain sizes of (a) BaxSr(1-x)TiO3 thin films (x=0~1) with 650oC, 700oC and 750oC annealing, and (b) Al-doped Ba0.65Sr0.35TiO3 thin films, calculated from the XRD patterns and FESEM graphs. 88
Table IV. Lattice constants of Al-doped Ba0.65Sr0.35TiO3 thin films with 650oC, 700oC and 750oC annealing, calculated from the XRD patterns. 89
Table V. The potential barrier heights of (a) Ba0.65Sr0.35TiO3 (b) Ba0.5Sr0.5TiO3, and (c) Al-doped Ba0.65Sr0.35TiO3 thin films. 102
Figures Captions
Fig.2-1 (a) BST perovskite structure (b) the shift of Ti ion as temperature is lower than Curier temperature. 7
Fig.2-2 The change of BST unit cell with various temperature8
Fig.2-3 The variation of (a) lattice constant and (b) dielectric constant of BST to various temperatures. 9
Fig.2-4 The diagrams of four polarization mechanisms12
Fig.2-5 The variation of the dielectric constant to applied electrical field13
Fig.2-6 The variation of BST polarization to applied bias. 17
Fig.2-7 The relationship between the polarization and frequency. 20
Fig.2-8 (a) dielectric constant (b) electrical conduction coefficient (c) loss factor that is corresponding to the delay time. 21
Fig.2-9 The schematic diagram of physical characteristics of a thin film. 24
Fig.2-10 Change in the dielectric constant with the film thickness with [Ba+Sr]/[Ti]=1.04 and [Sr]/[Ba+Sr]=0.6. The lines (-o-) and (-D-) show the molar concentration 0.3M and 0.15M, respectively. 26
Fig.2-11 Stress distribution in BST thin film (a) on MgO (b)LaO substrates30
Fig.2-12 The XRD pattern of BST thin films deposited on different bottom electrodes. 33
Fig.2-13 SEM micrographs and AFM surface morphology of BST thin films. Fig.(a) and (c), and Fig.(b) and (d) are the BST films deposited on Pt and RuO2 electrode, respectively. 34
Fig.2-14 The variations of the dielectric constant and tangent loss of BST thin films to various frequency on different electrodes35
Fig.2-15 The leakage current of BST thin films deposited on various bottom electrodes. 36
Fig.2-16 The dielectric constant and leakage current of as-deposited and annealed BST thin films on different bottom electrodes39
Fig.2-17 The XRD pattern of BST thin films annealed at various temperature. 40
Fig.2-18 The packing density of BST thin films with various annealed temperature41
Fig.2-19 The grain size and (110) peak intensity of BST thin films deposited on various electrode. 42
Fig.2-20 Schematic energy band diagram of Pt/BST/Pt capacitor affected by oxygen vacancies. 45
Fig.2-21 Effect of post-annealing atmosphere on the energy band diagram of Pt/BST/Pt capacitor46
Fig.2-22 The effect of oxygen partial pressure on defect density of BST thin film47
Fig.2-23 The effect of oxygen partial pressure on leakage current of BST thin film48
Fig.3-1 The flow chart of precursor and BST thin films coating61
Fig.3-2 The diagrams of dry-box62
Fig.3-3 Schematic diagrams of the X-ray signals with different incident angles.(a) large angle and (b) small angle. 63
Fig.4-1 TG/DTA measurement of Ba0.65Sr0.35TiO3 dried gels from 25oC to 1000oC. 67
Fig.4-2 FTIR spectrua of Ba0.3Sr0.7TiO3 thin films68
Fig.4-3 FTIR spectra of Ba0.65Sr0.35TiO3 thin films. 69
Fig.4-4 XRD patterns of Ba0.65Sr0.35TiO3 thin films. 70
Fig.4-5 The wide-scan XPS spectra of Ba0.65Sr0.35TiO3 thin film with RTA at 700oC. 72
Fig.4-6 The narrow-scan and curve fitting of XPS spectra of Ba2+ ions in BaxSr1-xTiO3 thin films. (a) x=0.5 and (b) x=0.65 77
Fig.4-7 The narrow-scan and curve fitting of XPS spectra of Sr2+ ions in BaxSr1-xTiO3 thin films. (a) x=0.5 and (b) x=0.6578
Fig.4-8 The narrow-scan and curve fitting of XPS spectra of Ti4+ ions in BaxSr1-xTiO3 thin films. (a) x=0.5 and (b) x=0.6579
Fig.4-9 The narrow-scan and curve fitting of XPS spectra of O2- ions in BaxSr1-xTiO3 thin films.(a) x=0.5 and (b) x=0.6580
Fig.4-10 SIMS depth profile of Ba0.65Sr0.35TiO3 thin films at 700oC annealing. 83
Fig.4-11 The XRD patterns of BaxSr(1-x)TiO3 thin films at 700oC annealing90
Fig.4-12 Lattice constants (a) for a-axis and (b) for c-axis of BaxSr(1-x)TiO3 thin films. The dash line shows the critical composition to distinguish the tetragonal and cubic structures at room temperature. 91
Fig.4-13 XRD patterns of x%Al-doped Ba0.65Sr0.35TiO3 thin films at 700oC annealing92
Fig.4-14 The lattice constant (a-axis) of Al-doped Ba0.65Sr0.35TiO3 thin films at 750oC annealing93
Fig.4-15 FESEM images of Ba0.5Sr0.5TiO3 thin films at various annealing temperatures (a) 650oC, (b) 700oC and (c) 750oC. 95
Fig.4-16 FESEM images of Ba0.65Sr0.35TiO3 thin films with various Al dopants (a) 1﹪,(b) 2﹪and (c) 3﹪96
Fig.4-17 Leakage current density vs. electric field strength in BST thin films (a) Ba0.65Sr0.35TiO3 and (b) Al-doped Ba0.65Sr0.35TiO398
Fig.4-18 AFM images of Pt electrode deposited assembly (a) TaN/SiO2Si and (b) Al2O3 substrates. 103
Fig.4-19 Ln(J/T2) vs. E1/2 of BST thin films (a) Ba0.65Sr0.35TiO3 and (b) Al-doped Ba0.65Sr0.35TiO3. 104
Fig.4-20 Ln(J/E) vs. E1/2 of BST thin films (a) Ba0.65Sr0.35TiO3 and (b) Al-doped Ba0.65Sr0.35TiO3. 105
Fig.4-21 Dielectric constants of Ba0.65Sr0.35TiO3 thin film at various annealing temperature. 108
Abstract
The BaxSr1-xTiO3 and Al-doped BST thin films were fabricated on Pt/TaN/SiO2/Si and Al2O3 substrates using sol-gel technique. The structure and thermal decomposition were investigated by means of thermogravimetric/differential thermal analysis (TG/DTA), Fourier transform infrared spectroscopy and X-ray diffractometer (XRD) analysis. The composition and chemical states of elements in BST thin films were characterized using X-ray photoelectron spectroscopy (XPS) technique. The results of thermal decomposition indicated that most of the organics such as acetate and carbonate decomposed below 420oC. The perovskite structure formed above 450oC. The convoluted spectrums of XPS patterns revealed that the chemical states of Ba, Sr, Ti and O are Ba2+, Sr2+, Ti4+ and O2-, respectively. The convoluted Ba photoelectron spectrum showed two different Ba bonding types, the typical BST mode and a relaxation-related mode. The oxygen photoelectron spectrum consisted of the normal perovskite peak and two high energy components which were due to the surface contaminations.
Aluminum was introduced to depress high leakage current due to the surface roughness of Al2O3 substrate. The doped Al substitute Ti-sites of BST perovskite structure. Two possible current transport mechanisms including Schottky emission and Poole-Frenkel emission are employed to explain the current characteristics of BST thin films. The different dominant conduction mechanisms are dependent on the electric field and the surface roughness of the substrates. The barrier heights of Schottky and Poole-Frenkel emission at forward bias are both higher than those at reverse bias, which may be attributed to the different roughness of pre-layers. The Al-doped BST thin films exhibit finer grains on the basis of XRD patterns and FESEM observations and higher potential barrier, thus leakage current is reduced.

References
1. W.J. Kim, W. Chang, S.B. Qadri, J.M. Pond, S.W. Horwitz and D.B. Chrisey, "Structure and Microwave Properties of (Ba,Sr)TiO3 Films Grown by Pulsed Laser Deposition", Appl. Phys. A 70 (2000) 313
2. W.J. Lee, C. Basceri, S.K. Streiffer, A.I. Kingon, D.Y. Yang, Y. Park, and H.G. Kim, "Ir and Ru Bottom Electrodes for (Ba, Sr)TiO3 Thin Films Deposited by Liquid Delivery Source Chemical Vapor Deposition", Thin Solid Films 323 (1998) 285
3. W.J. Lee, Y.M. Kim and H.G. Kim, "Pt-base Electrode and Effects on Phase Formation and Electrical Properties of High-Dielectric Thin Film", Thin Solid Films 269 (1995) 75
4. D.M. Tahan, L.C. Klein and and A. Safari, "Processing and Dielectric Property Evolution of Barium Strontium Titanate Thin Films Prepared by a Sol-Gel Technique", IEEE (1996)
5. D. Roy and S.B. Krupanidhi, "Excimer Laser Ablated Barium Strontium Titanate Thin Film for Dynamic Random Access Memory Application", Appl. Phys. Lett. 62 (10) (1993) 1056
6. S.G. Kim, S.B. Mah, N.W. Jang, D.S. Paik and C.Y. Park, "Post-Annealing in Oxygen Ambient for (Ba, Sr)TiO3 Thin Films Prepared by Pulsed Laser Deposition", Mater. Lett. 43 (2000) 254
7. I. Levin, R.D. Leapman, D.L. Kaiser, P.C. van Buskirk, S. Bilodeau and R. Carl, "Accommodation of Excess Ti in a (Ba,Sr)TiO3 Thin Film with 53.4% Ti Grown on Pt/SiO2/Si by Metalorganic Chemical-Vapor Deposition", Appl. Phys. Lett. 75 (9) (1999) 1299
8. Y. Tsunemine, T. Okudaira, K. Kashihara, K. Hanafusa, A. Yutani, Y. Fujita, M. Matsushita, H. Itoh and H. Miyoshi, "A Manufacturable Integration Technology of Sputter-BST Capacitor with a Newly Proposed Thick Pt Electrode", IEEE (1998)
9. T.S. Kang, Y.S. Kim and J.H. Je, "Thermal Stability of RuO2, BaxSr1-xTiO3/RuO2, and BaxSr1-xTiO3/Pt/Ti/SiO2 on Si(100)", Mater. Res. Soc. 15 (9) (2000) 1955
10. N.V. Giridharan, R. Varatharajan, R. Jayavel, P. Ramasamy, "Fabrication and Characterisation of (Ba,Sr)TiO3 Thin Films by Sol-Gel Technique Through Organic Precursor Route", Mater. Chem. Phys. 65 (2000) 261
11. I. Suzuki, M. Ejima, K. Watanable, Y.M. Xiong and T. Saitoh, "Spectrospic Ellipsometry Characterization of Ba0.7Sr0.3TiO3 Thin Films Prepared by the Sol-Gel Method", Thin Solid Films, (1998) 313
12. D. Wu, A. Li, Z. Liu, H. Ling, C.Z. Ge, X. Liu, H. Wang, M. Wang, P. Lu, N. Ming, "Fabrication and Electric Properties of Sol-Gel Derived (Ba,Sr)TiO3 Thin Films with Metallic LaNiO3 Electrode", Thin Solid Films 336 (1998) 172
13. K.M.S. Khalil, "Low Temperature Evolution of Crystalline BaTiO3 from Alkali-Metal Free Precursor using Sol-Gel Process", Mater. Res. Inno. 2 (1999) 256
14. P.C. Chen, H. Miki, Y. Shimamoto, Y. Matsui, M. Hiratani and Y. Fujisaki, "Effects of Post-Annealing Temperatures and Ambient Atmospheres on the Electrical Properties of Ultrathin (Ba,Sr)TiO3 Capacitors", Jap. J. Appl. Phys. 37 (1998) 5112
15. M.S. Tsai and T.Y. Tseng, "Effect of Oxygen to Argon Ratio on Defects and Electrical Conductivities in Ba0.47Sr0.53TiO3 Thin Film Capacitors", J. Phys. D：Appl. Phys. 32 (1999) 2141
16. T.G. In and S. Baik, "Leakage Current of Al- or Nb-doped Ba0.5Sr0.5TiO3 Thin Films by rf Magnetron Sputtering", J. Mater. Res. 13 (4) (1998) 990
17.J.M. Wang "Ceramic Technology Handbook", Ying-Jie Co. Press, Taiwan
18. C. Basceri, S. K. Streiffer and Augus I. Kingon, J. Appl. Phys. 82 (2000) 2497
19. G. Ti and M. Sayer, "Sol-gel Processing of Complex Oxide Films", Ceramic Bulletin 30 (7) (1991) 1173
20. A. Tsuzuki, K. Kato, K. Kusumoto and Y. Torii, "Preparation and Characterization of Ba1-xSrxTiO3 Films by Sol-Gel Processing", J. Mater. Sci. 33 (1998) 3055
21. W. Chang, C.M. Gilmore, W.J. Kim, J.M. Pond, S.W. Kirchoefer, S.B. Qadri, D.B. Chirsey and J.S. Horwitz, "Influence of Strain on Microwave Dielectric Properties of (Ba, Sr)TiO3 Thin Films", J. Appl. Phys. 87 (6) (2000) 3044
22. W. Chang, J.S. Horwitz, A.C. Carter, J.M. Pond, S.W. Kirchoefer, C.M. Girmole, and D.B. Chrisey, "The Effect of Annealing on the Microwave Properties of Ba0.5Sr0.5TiO3 Thin Films", Appl. Phys. Lett. 7 (7) (2000) 1033
23. S.I. Jang and H.M. Jang, "Leakage-Current Characteristics of Sol-Gel-Derived Ba1-xSrxTiO3 (BST) Thin Film", Ceram. Inter. 26 (2000) 421
24. S.H. Paek, J. Won, K.S. Lee, J.Y. Seong, S.H. OH, M.S. Jeon, D.K. Choi, J.P. Mah and C.S. Park, "Leakage Current Mechanism of (BaSr)TiO3 Film with Various (Ba+Sr)/Ti Ratio on a RuO2 Electrode", J. Mater. Sci. Lett. 17 (1998) 1457
25. M.S. Tsai and T.Y. Tseng, "Conduction Mechanism and Temperature-Dependent Current-Voltage in (Ba,Sr)TiO3 Thin Film", J. Electrochem. Soc. 15 (8) (1998) 2853
26. E. Loh, "A Model of dc Leakage in Ceramic Capacitors", J. Appl. Phys. 53 (1982) p6229
27. Y.C. Choi and B.S. Lee, "Bottom Electrode Dependence of the Properties of (Ba, Sr)TiO3 Thin Film Capacitors", Mater. Chem. Phys. 61 (1999) 124
28. M.S. Tsai and T.Y. Tseng, "Effect of Bottom Electrode on Resistance Degradation and Breakdown of (Ba, Sr)TiO3 Thin Films", IEEE (2000)
29. M.S. Tsai, S.C. Sun and T.Y. Tseng, "Effect of Bottom Electrode Materials and Annealing Treatments on the Electrical Characteristics of Ba0.47Sr0.53TiO3 Film Capacitors", J. Am. Ceram. Soc. 82 (1999) 351
30. S.C. Sun and M.S. Tsai, "Effect of Bottom Electrode Materials on the Electrical and Reliability Characteristics of (Ba,Sr)TiO3 Capacitors", IEEE (1997)
31. S. Hong, H. Bak, I. An and O.K. Kim, "Microstructural and Electrical Properties of BaxSr1-xTiO3 Thin Films on Various Electrodes", Jap. J. Appl. Phys. 1 39 (4) A (2000) 1796
32. M.S. Tsai, S.C. Sun, and T.Y. Tseng, "Effect of Bottom Electrode Materials on the Electrical and Reliability Characteristics of (Ba,Sr)TiO3 Capacitors", IEEE (1999)
33. J.H. Joo, Y.C. Jeon, J.M. Seon, K.Y. Oh, J.S. Roh and J.J. Kim, "Effects of Post Annealing on the Conduction Properties of Pt/(Ba, Sr)TiO3/Pt Capacitors for Dynamic Random Access Memory Application", Jap. J. Appl. Phys. 36 (1997) 4382
34. Y.B. Lin and J.Y. Lee, "The Temperature Dependence of the Conduction Current in Ba0.5Sr0.5TiO3 Thin Film Capacitors for Memory Device Application", J. Appl. Phys. 87 (4) (2000) 1841
35. M.H. Frey and D.A. Payne, "Nanocrystalline Barium Titanate：Evidence for the Absence of Ferroelectricity in Sol-Gel Derived Thin-Layer Capacitors", Appl. Phys. Lett. 63 (20) (1993) 2753
36. V.M. Vasiljev, K.A. Vorotilov, M.I. Yanovskaya, L.I. Solovjeva and A.S. Sigov, "Sol-gel Derived Barium-Strontium Titanate Films", J. Sol-Gel Sci. Tech. 13 (1998) 877
37. Y.F. Kua and T.Y. Tseng, "Structure-Related Optical Properties of Rapid Thermally Annealed Ba0.7Sr0.3TiO3 Thin Films", Mater. Chem. Phys. 61 (1999) 244
38.R.E. Reed-Hill and R. Abbaschian, Physical Metallurgy Principles 3rd editon, International Thomson Poblishing Press, Singapore
39. N.Ichinose and T.ogiwara, "Preparation and Rapid Thermal Annealing Effect of (Ba,Sr)TiO3 Thin Films", 34 (1995) 5198-5201
40. W.J. Kim, S.B. Qadri, J.M. Pond, S.W. Kirchoefer, D.B. Chrisey and J.S. Horwitz, "Microwave Properties of Tetragonally Disorted (Ba0.5Sr0.5)TiO3 Thin Films", App. Phys. Lett. 76 (9) (2000) 1185
41. M. Sedlar, M. Sayer and L. Weaver, "Sol-Gel Processing and Properties of Cerium Doped Barium Strontium Titanate Thin Films", J. Sol-Gel Sci. Tech. 5 (1995) 201
42. T.G. In and S. Baik, "Leakage Current of Al- or Nb-Doped Ba0.5Sr0.5TiO3 Thin Films by rf Magnetron Sputtering", J. Mater. Res. 13 (4) (1998) 990
43. S.I. Jang and H.M. Jang, "Structure and Electrical Properties of Boron-Added (Ba,Sr)TiO3 Thin Films by the Sol-Gel Method", Thin Solid Films 330 (1998) 89
44. M. Hafid, S. Takeoka, S. Nishida, T. Fukami, and J. Sheng, "Dielectric and Conduction Properties in Nickel Doped Barium Strontium Titanate Ceramics", Jap. J. Appl. Phys. 37 (1998) 3370
45.G.Subramanyam, F. Van Keuls, and F.A. Miranda, International, IEEE MTT-S 2 (1998) 1011
46.T.Y. Tseng, "The Applications of BST Thin Films in Microwave Communication", Electronic Monthly Magazine Publishing Press, 6 (10) 2000 p.146
47. M.P. Seah, "Background Subtraction I. General Behavior of Tougaard-style Backgrounds in AES and XPS", Sur. Sci. 420 (1999) 285
48. M. Jo, "Direct, Simultaneous Determination of XPS Background and Inelastic Differential Cross-section Using Tougaard Algorithm", Sur. Sci. 328 (1994) 191
49. Y. Adachi, S. Kohiki, K. Wagatsuma and M. Oku, "Changes in the Chemical State of Monocrystalline SrTiO3 Surface by Argon Ion Bombardment", Appl. Sur. Sci. 143 (1999) 272
50. M. Oku, H. Matsuta, K. Wagatsuma, Y. Waseda and S. Kohiki, "Removal of Inelastic Scattering at Part From Ti2p XPS Spectrum of TiO2 by Deconvolution Method Using O1s as Response Function", J. Electr. Spec. Related Phen. 105 (1999) 211
51. H.Y. Tian, W.G. Luo, X.H. Pu, P.S. Qiu, X.Y. He and A.L. Ding, "Synthesis and Analysis of Thermal Decomposition and Microstructure of Sr-Doped Barium Titanate Alkoxide Derived Precipitate and Thin Films", Thermochemica Acta 360 (2000) 57
52. M.N. Kamalasanan, N.D. Kumar and S. Chandra, "Structural and Microstructural Evolution of Barium Titanate Thin Films Deposited by the Sol-Gel Process", J. Appl. Phys. 76 (8) (1994) 4603
53. M. Wada and T. Ohtuki, "Infrared Study of BaTiO3 Thin Films", Physica B 219? (1996) 635
54. D.P. Birnie, "Esterification Kinetics in Titanium Isopropoxide-Acetic Acid Solutions", J. Mater. Sci. 35 (2000) 367
55. L.G. Wade, Jr., "Appendix-2 of Organic Chemistry", Prentice-Hall Inc. Press, 1995 3rd edition
56. J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bombern and J. Chastain eds., "Handbook of X-ray Photoelectron Spectroscopy", Perkim-Elwer co. Press, Eden Prairie, MN, USA, 1992.
57. B. Demri, M. Hage-Ali, M. Moritz, J.L. Kahn and D. Muster, "X-ray Photoemission Study of the Calcium/Titanium Dioxide Interface", Appl. Sur. Sci. 108 (1997) 245
58. S.A. Nasser, "X-Ray Photoelectron Spectropy Study on the Composition and Structure of BaTiO3 Thin Films Deposited on Silicon", Appl. Sur. Sci. 157 (2000) 14
59. C. Miot, C. Proustz, E. Husson, R. Erre, G. Blondiaux, J. M. Beny and J. P. Coutures, "Characterization of Barium Titanate Ceramics Obtained by a Chemical Route after Laser Ablation", Mater. Sci. Eng. B45 (1997) 17
60. C.J. Lu, A.X. Kuang and G.Y. Huang, "X-ray Photoelectron Spectroscopy Study on Composition and Structure of Sol-Gel Derived PbTiO3 Thin Films", J. Appl. Phy. 80 (1) (1996) 202
61. M. Viviani, M. T. Buscaglia, P. Nanni, R. Parodi, G. Gemme and A. Dacca, "XPS Investigation of Surface Properties of Ba(1-x)SrxTiO3 Powders Prepared by Low Temperature Aqueous Synthesis", J. Europ. Ceram. Soc. 19 (1999) 1047
62. V. Craciun and R. K. Singh, "Characteristics of the Surface Layer of Barium Strontium Titanate Thin Films Deposited by Laser Ablation", App. Phys. Lett. 76 (14) (2000) 1932
63. J.A. T. Verhoeven and H. van Doveren, "XPS Studies on Ba, BaO and the Oxidation of Ba", Application Sur. Sci. 5 (1980) 361
64. S.M. Mukhopadhyay and Tim C.S. Chen, "Surface Chemical States of Barium Titanate: Influence of sample processing", J. Mater. Res. 10 (6) (1995) 1502
65. S.Y. Wu, J.G. Duh and B.S. Chiou, "Thermal Evolutions, and Peak Deconvolutions of XPS for (Ba,Sr)TiO3 Thin Films", Submitted by Thin Solid Films
66. W.D. Kindery, H.K. Bowen and D.R. Uhlmann, " Introduction to Ceramics", 2nd edition, Wiley Press, New York. 1975
67. B.D. Cullity, "Elements of X-ray Diffraction", 2nd edition, Addison Wesley Press, California
68. C.S. Hwang, S.O. Park, C.S. Kang, H.J. Cho, H.K. Kang, S.I. Lee and M.Y. Lee, Appl. Phys. Lett. 67 (1995) 2819
69. J.H. Joo, Y.C. Jeon, J.M. Seon, K.Y. Oh, J.S. Roh and J.J. Kim, "Effects of Post-Annealing on the Conduction Properties of Pt/(Ba,Sr)TiO3/Pt Capacitors for Dynamic Random Access Memory Application", Jpn. J. Appl. Phys. 36 (1997) 4382
70. Y.M. Lee, "Solid State Electronics", Chwa Publisher Press, Taiwan 1995 p.439
71. S.M. Sze, "Current Transport and Maximum Dielectric Strength of Silicon Nitride Films", J. App. Phys. 36 (7) (1967) 2951
72. C. Basceri, S.K. Streiffer and A.I. Kingon, J. Appl. Phys. 82 (1997) 2497
73. T.B. Wu and J.N. Lin, "Transition of Compensating Defect Mode in Niobium-Doped Barium Titanate", J. Am. Ceram. Soc. 77 (3) (1994) 759
74. D.M. Smyth, M.P. Harmer and P. Peng, "Defect Chemistry of Relaxor Ferroelectrics and the Implication for Dielectric Degradation", J. Am. Ceram. Soc. 72 (12) (1989) 2276
75. K.C. Kao and W. Huang, "Electrical Transport in Solid", Pergamon Press, Oxford, 1981, p.86
76. K.N. Tu, J.W. Mayer and L.C. Feldman, "Electronic Thin Film Science for Electrical Engineers and Materials Scientists", Macmillan Publishers, New York, 1992, p.236