CHEMICAL VAPOR DEPOSITION OF THIN FILM MATERIALS FOR ...

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simply evacuating with vacuum pump, substrate exposure to the gas phase oxidant or reductant chemicals, and the last step of purging the deposition chamber with inert gas. A schematic diagram of steps for a typical ALD cycle is showed in Fig.2. Fig. 2. A typical ALD cycle with oxidation reaction. As shown in Fig.2, the first step in an ALD repeating cycle is adsorption of a gas phase metal containing precursors onto a substrate surface. To satisfy the criteria of self-terminating adsorption, chemisorption, which has much higher bonding energy to the substrate surface than physisorption, is necessary. For a chemisorption process, usually new chemical bonds between the precursor molecule and substrate surface will form and simultaneously certain volatile reaction products will be generated which will be purged and pumped out of the deposition chamber in the following step. In addition, the thermal stability of the adsorbed species has to be high enough to eliminate surface decomposition or intra reaction of the precursor itself, which will also induce non self-terminating behavior. The next step is purging/evacuating the deposition chamber, which should sweep out most of the residual gas phase and surface physisorbed reactive species generated by the previous step. After purging/evacuating, the risk of gas phase reaction/nucleation by introducing the oxidant/reducer chemicals into the chamber is minimized. Also, the substrate surface is covered uniformly with chemisorbed reactive species 7
for the next reaction step as shown in Fig.2. It has been found that the surface coverage after this step is usually a fraction of a monolayer, which is due to the effect of steric hindrance of the ligands and thus certain surface reactive sites will not be covered. The third step is to introduce oxidant/reducer chemicals into the deposition chamber to react with the active sites of the previously covered surface. This step is mainly to oxidize or reduce the previously adsorbed surface by substituting the surface organic ligands with new reactive bonds for the reaction with precursor molecules of the next cycle. Usually this new formed surface has the same chemical bonds as the bare substrate surface. The last step is to purge/evacuate the chamber to get rid of the reactive oxidants/reducers and after this step the substrate is ready to start a new cycle of deposition. ALD has few advantages such as digital thickness control at the atomic level, perfect 3D conformality, large area thickness uniformity, low defect density, possibility of low temperature deposition (RT~400˚C), and atomically smooth topography. The main disadvantage of the ALD method is its low growth rate, which is usually less than one atomic layer per cycle. This low growth rate has limited ALD method mainly to very thin layers deposition, such as the gate dielectric layer in the MOSFET structure, which is only 2 or 3 nanometers thickness.[8] 1.1.3 Direct Liquid Injection Chemical Vapor Deposition (DLICVD) CVD technique coupled with various liquid injection/vaporization equipment is usually defined as direct liquid injection CVD (DLICVD), in which the precursor source is in the state of liquid solution and injected into the vaporization equipment to generate vapor for the CVD reaction. By using DLICVD, all the precursors can be prepared as a single source, i.e. dissolving them (liquid or solid) into an appropriate solvent. After injection into the vaporizer, these precursors can be vaporized simultaneously and therefore the molar ratio between different 8
Page 1 and 2: CHEMICAL VAPOR DEPOSITION OF THIN F
Page 3 and 4: ABSTRACT Chemical vapor deposition
Page 5 and 6: DEDICATION This dissertation is ded
Page 7 and 8: φ In-plane tilt angle of X-ray dif
Page 9 and 10: ACKNOWLEDGMENTS It is my pleasure t
Page 11 and 12: CONTENTS ABSTRACT .................
Page 13 and 14: 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: one can uniformly deliver precursor
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 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 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
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
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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