CHEMICAL VAPOR DEPOSITION OF THIN FILM MATERIALS FOR ...

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Another way to break through the limitation of vaporization is the technique of direct liquid injection, in which the precursor containing the liquid source is injected into a vaporizer and is volatilized there before it’s delivered into the CVD reactor by a carrier gas. In this way, the vaporization temperature can be dramatically decreased and the introduction of precursor can be accurately controlled by a sensitive liquid flow meter. A couple of studies have been reported based on this technique in CVD of BaTiO3 or (Ba,Sr)TiO3 thin films.[114,136,141] The reported results show that this can be a very promising technique for the deposition of high quality and thick BaTiO3 films. Considering the desirability of thick (tens of microns) and high quality ferroelectric films in the study of magnetoelectric coupling effects in layered heterostructures,[142] our research on CVD of BaTiO3 films will take advantage of the direct liquid injection technique. 47
CHAPTER 3. PLASMA ENHANCED ATOMIC LAYER DEPOSITION OF HAFNIUM 3.1 Introduction NITRIDE FILMS Chemical vapor deposition of HfN can make films of high conformality and thus provide the possibility of fabricating high aspect ratio microelectronic structures. One of the challenges for this method is the selection of appropriate chemicals. Hafnium amide precursors have been successfully used in the deposition of HfO2, Hf3N4 and HfN by reacting with oxygen (O2), ammonia (NH3) and dimethyl hydrazine (H2NN(CH3)2) respectively.[63,67,70] For the deposition of HfN using dimethyl hydrazine, usually a high substrate temperature (600˚C~800˚C) is needed to initiate the reaction, which is not appropriate for certain thermal sensitive materials used in the microelectronic devices. Hydrogen plasma which has much higher reactivity than hydrazine can be used in low temperature plasma enhanced ALD process of HfN thin films.[71,72] In this chapter, the hafnium precursor tetrakis (dimethylamido) hafnium (IV) (TDMAH) used for thin film growth is studied first, i.e., in-situ monitoring of adsorption and reaction behavior of TDMAH on hydrogenated Si(100) by ATR-FTIR. It's important to understand the thermal decomposition and surface adsorption behavior of this precursor for ALD thin film growth, because it is directly related to the film contamination and interfacial bonding information.[143] PEALD of HfN thin film growth by using TDMAH and hydrogen plasma is studied. The as-deposited thin films were characterized by XPS, AFM, XRD, SEM and TEM to study the chemical composition, surface morphology and crystal structure information. Thin film 48
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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 ................
Page 15 and 16: LIST OF TABLES Table 1. Hafnium ami
Page 17 and 18: indicated by the complex FMR curve.
Page 19 and 20: Fig. 49. Ferromagnetic resonance cu
Page 21 and 22: growth rate, good step coverage and
Page 23 and 24: growth of thin film oxides due to t
Page 25 and 26: one can uniformly deliver precursor
Page 27 and 28: for the next reaction step as shown
Page 29 and 30: Fig. 3. Schematic of a typical dire
Page 31 and 32: is predominantly dependent on syste
Page 33 and 34: J r J A -D n b-n 0 δ n or for the
Page 35 and 36: surface passivation with certain in
Page 37 and 38: ay spectroscopy (EDS), Wavelength d
Page 39 and 40: incidence angle is larger than cert
Page 41 and 42: 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: precursor vaporization process, e.g
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 and 94: film growth region. The properties
Page 95 and 96: solution was accurately controlled
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
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Fig. 53. ϕ-scan of nickel ferrite
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Surface roughness characterized by
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Fig. 56. X-ray diffraction θ-2θ c
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4.4 Conclusion In summary, we have
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CHAPTER 5. DIRECT LIQUID INJECTION
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eaction zone of the tube furnace is
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Fig. 58. X-ray diffraction characte
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interface. This phenomenon probably
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6.1 Conclusion CHAPTER 6. CONCLUSIO
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the temperature range of 600˚C to
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such as PMN-PT and PZN-PT. CVD proc
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[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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