CHEMICAL VAPOR DEPOSITION OF THIN FILM MATERIALS FOR ...

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substrates such as MgO(111), and piezoelectric SrTiO3(100), PMN-PT (Pb(Mg1/3Nb2/3)O3- PbTiO3) (100), and PZN-PT (Pb(Zn1/3Nb2/3)O3-PbTiO3) (100) is also investigated under certain experimental conditions. 4.2.1 Experimental Details Nickel ferrite films are deposited on MgAl2O4 (100) and MgO (100) substrates in a horizontal 1.5 inch diameter quartz tube furnace. The DLI-CVD experimental set-up is shown in Fig.38. Fig. 38. Experimental set-up of DLI-CVD system for the growth of nickel ferrite films. As shown in Fig.38, The CVD reactor is a three zone low pressure quartz tube furnace. The tube reactor, with a diameter of 1.5 in. and length of 50 in., was pumped down to the reaction pressure (12 Torr) by a rotary vane vacuum pump (Leybold, Trivac). Ni (acac)2 (98%) and Fe(acac)3 (99%), bought from Sigma-Aldrich, were used as metal organic precursors without any further purification. These precursors were dissolved in N, N-dimethyl formamide (DMF) in a molar ratio of 1:2 as the source for liquid injection. Ultrahigh purity He (20 psi) was used to pressurize the liquid flow from solution container to the vaporizer. The flow rate of the liquid 75
solution was accurately controlled by a Brooks Quantim liquid MFC (10 g/h, full range) connected to the DLI200 vaporizer system. Ultrahigh purity argon gas was used as the carrier gas, which served both as the vaporization medium and the delivery gas. The liquid vaporization process is accelerated by a sequential input of mechanical and thermal energy. At the vaporizer inlet, where the liquid and carrier gas flow intersect, is an atomizer, which breaks up the entering fluid into fine droplets (2~5μm) because of a large pressure drop. Efficient heat and mass transport between the fine droplets and the preheated carrier gas (Ar) results in the metal-organic precursors being homogenously entrained in the solvent vapor and carried into the reactor without premature decomposition. Ultrahigh purity oxygen was used as the oxidant. Atomically polished single crystals such as MgAl2O4 (100) and MgO (100) of dimensions 5mm×5mm×0.5mm from CrysTec Gmbh were used as substrates. Before loading into the reactor, the substrates were ultrasonically cleaned sequentially in acetone and isopropanol and then blow dried with N2. The vaporizer system was cleaned with pure DMF solvent after each run. Typical processing conditions are summarized in Table 4. Table 4. Typical processing conditions for DLI CVD of epitaxial NiFe2O4 films. Substrate MgAl2O4 (100) / MgO (100) Reaction pressure (Torr) 12 Growth temperature (˚C) 500-800 Concentration of solution (Fe(acac)3, mol/L) 0.067 Solution flow rate (g/hr) 6 Ar carrier gas flow rate (sccm) 300 Vaporizer temperature (˚C) 175 Oxygen flow rate (sccm) 300 Prior to investigation of the CVD process conditions, we optimized the vaporizer operation parameters (including precursor solution injection rate, carrier gas (Argon) flow rate, vaporizer temperature, inlet and outlet pressures) by inspecting the surface morphology and 76
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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
Page 43 and 44: 1.2.3.3 X-ray Diffraction (XRD) X-r
Page 45 and 46: exhibit diffraction peaks in the no
Page 47 and 48: (nanometers to tens of nanometers),
Page 49 and 50: strongest absorption of microwave s
Page 51 and 52: pinch-off to indicate the lack of a
Page 53 and 54: coupling is from unbound ferrite-fe
Page 55 and 56: diffusion barrier material in micro
Page 57 and 58: Fig. 14. A cross sectional scanning
Page 59 and 60: In spite of the same spinel structu
Page 61 and 62: ferrites has been investigated exte
Page 63 and 64: systems is showed in Fig.18.[83] As
Page 65 and 66: precursor vaporization process, e.g
Page 67 and 68: CHAPTER 3. PLASMA ENHANCED ATOMIC L
Page 69 and 70: the initial surface chemistry for t
Page 71 and 72: delay time of 2 seconds between spe
Page 73 and 74: Kcal/mol respectively. The stronger
Page 75 and 76: negative slope) behavior in the pum
Page 77 and 78: the existence of both physisorbed a
Page 79 and 80: decomposition products (Hf-H) and g
Page 81 and 82: dried by ultra high purity N2 gas.
Page 83 and 84: pressure for XPS analysis is around
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: film growth region. The properties
Page 97 and 98: size). For the rocking curve analys
Page 99 and 100: oxygen does not participate in the
Page 101 and 102: ecause vapor velocity cannot be cha
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 and 132: interface. This phenomenon probably
Page 133 and 134: 6.1 Conclusion CHAPTER 6. CONCLUSIO
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
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[136]. J. Zhao, V. Fuflyigin, F. Wa
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APPENDIX A: LabVIEW PROGRAM FOR PEA
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APPENDIX B: TDMAH MOLECULAR STRUCTU
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H 18 B19 2 A18 1 D17 H 18 B20 2 A19
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