CHEMICAL VAPOR DEPOSITION OF THIN FILM MATERIALS FOR ...

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XRD characterization has showed pure BaTiO3 phase, F elements can still exist in the film in amorphous phase and affect thin film physical property. 5.4 Conclusion Epitaxial growth of BaTiO3 films on MgO (100) substrate has been obtained by DLI- CVD technique. Good single crystal quality has been illustrated by the results of ω and ϕ-scan. Thin film growth rate of ~0.5 μm hr is achieved under our experimental conditions. Surface and cross sectional morphology characterization shows large surface roughness and interface voids, which can be contributed to the island mode thin film growth. Incorporation of small amount of F elements in the thin film has been verified by XPS analysis. Instead of forming crystalline BaF2 phase, the F elements bonds to the Ba ions in amorphous state. Although we have obtained epitaxial growth of BTO films, few issues related to thin film quality still need to be improved, such as the film morphology, growth rate, and chemical contamination. Either optimizing CVD processing conditions or selecting more appropriate Ba precursor is believed to be capable of improving these issues in certain degree. 113
6.1 Conclusion CHAPTER 6. CONCLUSION AND FUTURE WORK Chemical vapor deposition (CVD) of thin film materials with excellent electronic or magnetic properties has been investigated in this dissertation. Specific CVD techniques including plasma enhanced atomic layer deposition (PEALD) and direct liquid injection CVD (DLI-CVD) have been employed based on the requirements of practical thin film application. The essential work consists of chemical precursor selection and characterization, CVD processing, and thin film characterization. The results of thin film characterization could provide important information for the optimization of CVD processing conditions and thus in turn to improve the thin film quality. The results of PEALD of hafnium nitride (HfN), DLI-CVD of nickel ferrite (NiFe2O4), lithium ferrite (LiFe5O8), and barium titanate (BaTiO3) are summarized below. 6.1.1 PEALD of HfN thin films Tetrakis (dimethylamido) hafnium (IV) (TDMAH) is used as the metal organic precursor for PEALD of HfN thin film. Its adsorption and reaction on hydrogenated Si(100) surface has been investigated by in-situ ATR-FTIR. It has been found that for temperatures below 100˚C, physisorption is the main mode of TDMAH adsorbing onto the crystal surface and no obvious surface Si-H bonds breaking. These physisorbed TDMAH molecules have weak bonding energy to the surface and easy to desorb. At temperatures between 100˚C and 150˚C, surface adsorbed TDMAH molecules start to decompose and newly emerging IR peaks at 1591 cm -1 and 1639 cm - 1 are assigned to N=C and Hf-H vibrational mode respectively based on a β-hydride elimination mechanism. The decomposition species on the surface has been found hard to desorb at 150˚C, 114
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CHEMICAL VAPOR DEPOSITION OF THIN F
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ABSTRACT Chemical vapor deposition
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DEDICATION This dissertation is ded
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φ In-plane tilt angle of X-ray dif
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ACKNOWLEDGMENTS It is my pleasure t
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CONTENTS ABSTRACT .................
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3.2.1 Introduction ................
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LIST OF TABLES Table 1. Hafnium ami
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indicated by the complex FMR curve.
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Fig. 49. Ferromagnetic resonance cu
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growth rate, good step coverage and
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growth of thin film oxides due to t
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one can uniformly deliver precursor
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for the next reaction step as shown
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Fig. 3. Schematic of a typical dire
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is predominantly dependent on syste
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J r J A -D n b-n 0 δ n or for the
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surface passivation with certain in
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ay spectroscopy (EDS), Wavelength d
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incidence angle is larger than cert
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epresenting those characteristic ph
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1.2.3.3 X-ray Diffraction (XRD) X-r
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exhibit diffraction peaks in the no
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(nanometers to tens of nanometers),
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strongest absorption of microwave s
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pinch-off to indicate the lack of a
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coupling is from unbound ferrite-fe
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diffusion barrier material in micro
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Fig. 14. A cross sectional scanning
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In spite of the same spinel structu
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ferrites has been investigated exte
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systems is showed in Fig.18.[83] As
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precursor vaporization process, e.g
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CHAPTER 3. PLASMA ENHANCED ATOMIC L
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the initial surface chemistry for t
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delay time of 2 seconds between spe
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Kcal/mol respectively. The stronger
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negative slope) behavior in the pum
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the existence of both physisorbed a
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decomposition products (Hf-H) and g
Page 81 and 82: dried by ultra high purity N2 gas.
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Page 85 and 86: Hf and N elements, incorporation of
Page 87 and 88: [150,151] This is a unique feature
Page 89 and 90: software. The thickness results are
Page 91 and 92: CHAPTER 4. DIRECT LIQUID INJECTION
Page 93 and 94: film growth region. The properties
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Page 97 and 98: size). For the rocking curve analys
Page 99 and 100: oxygen does not participate in the
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Page 103 and 104: Fig. 40. Cross-sectional view by fi
Page 105 and 106: the MgAl2O4 substrate confirms cube
Page 107 and 108: pattern. Fig.44(b) has diffraction
Page 109 and 110: We have used an AGM (Alternating Gr
Page 111 and 112: as derived equations for different
Page 113 and 114: deposited at 600˚C is the lowest.
Page 115 and 116: wave states degenerate with the FMR
Page 117 and 118: Fig. 53. ϕ-scan of nickel ferrite
Page 119 and 120: Surface roughness characterized by
Page 121 and 122: Fig. 56. X-ray diffraction θ-2θ c
Page 123 and 124: 4.4 Conclusion In summary, we have
Page 125 and 126: CHAPTER 5. DIRECT LIQUID INJECTION
Page 127 and 128: eaction zone of the tube furnace is
Page 129 and 130: Fig. 58. X-ray diffraction characte
Page 131: interface. This phenomenon probably
Page 135 and 136: the temperature range of 600˚C to
Page 137 and 138: such as PMN-PT and PZN-PT. CVD proc
Page 139 and 140: [18]. L. S.-J. Peng, X. X. Xi, B. H
Page 141 and 142: [54]. B. O. Johansson, J. -E. Sundg
Page 143 and 144: [96]. J. D. Adam, S. V. Krishnaswam
Page 145 and 146: [136]. J. Zhao, V. Fuflyigin, F. Wa
Page 147 and 148: APPENDIX A: LabVIEW PROGRAM FOR PEA
Page 149 and 150: APPENDIX B: TDMAH MOLECULAR STRUCTU
Page 151 and 152: H 18 B19 2 A18 1 D17 H 18 B20 2 A19
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