njit-etd2000-029 - New Jersey Institute of Technology

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15 Table 1.1 Evaporation vs. Sputtering Evaporation Sputtering A. Production of Vapor Species 1. Thermal evaporation mechanism Ion bombardment and collisional momentum transfer 2. Low kinetic energy of evaporant atoms 2. High kinetic energy of sputtered atoms (@ 1200K , E = 0.1 eV) (E = 2-30 eV) 3. Evaporation rate — 1.3 x 10 17 atoms/cm2- 3. Sputter rate ~ 3 x 10 16 atoms/cm2-sec sec 4. Directional evaporation according to 4. Directional sputtering according to cosine law cosine law at high sputter rates 5. Fractionation of multicomponent alloys, 5. Generally good maintenance of target decomposition, and dissociation of stoichiometry, but some dissociation of compounds compounds 6. Availability of high evaporation source purities 1. Evaporant atoms travel in high or ultrahigh vacuum (~ 10-6 - 10-10 ton) ambient B. The Gas Phase 6. Sputter target of all materials are available; purity varies with material 1. Sputtered atoms encounter high pressure discharge region (~ 100 mtorr) 2. Thermal velocity of evaporant 10 5 cm/sec 2. Neutral atom velocity ~ 5 x 104 cm/sec 3. Mean-free path is larger than evaporantsubstrate spacing; evaporant atoms undergo substrate spacing; Sputtered atoms undergo 3. Mean-free path is less than target- no collisions in vacuum many collisions in the discharge C. The Condensed Film 1. Condensing atoms have relatively low 1. Condensing atoms have high energy energy 2. Low gas incorporation 2. Some gas incorporation 3. Grain size generally larger than for 3. Good adhesion to substrate sputtered film 4. Few grain orientations (textured films) 4. Many grain orientations
16 Chemical vapor deposition is discussed next. Some factors that distinguish PVD from CVD are: 1. Reliance on solid or molten sources 2. Physical mechanisms (evaporation or collisional impact) by which source atoms enter the gas phase 3. Reduced pressure environment through which the gaseous species are transported. 4. General absence of chemical reactions in the gas phase and at the substrate surface (reactive PVD processes are exceptions). 1.1.2 Chemical Vapor Deposition Chemical Vapor Deposition (CVD) is one of the most important methods of film formation used in the fabrication of very large scale integrated (VLSI) silicon circuits, as well as of microelectronic solid state devices in general. It may be defined as the formation of a non-volatile solid film on a substrate by the reaction of vapor phase chemicals (reactants) that contain the required constituents. In this process, chemicals in the gas or vapor phase are reacted at the surface of the substrate where they form a solid product. A large variety of materials, practically all those needed in microelectronic device technology, can be created by CVD. These materials comprise insulators and dielectrics, elemental and compound semiconductors, electrical conductors, superconductors and magnetics. In addition to its unique versatility, this materials synthesis and vapor phase growth method can operate efficiently at relatively low temperatures. For example, refractory oxide glasses and metals can be deposited at temperatures of only 300° to 500°C. This feature is very important in advanced VLSI devices with short channel lengths
Page 1 and 2: Copyright Warning & Restrictions Th
Page 3 and 4: ABSTRACT SYNTHESIS AND CHARACTERIZA
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Page 9 and 10: This thesis is dedicated to my pare
Page 11 and 12: TABLE OF CONTENTS Chapter Page 1 IN
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Page 17 and 18: LIST OF TABLES Table Page 1.1 Evapo
Page 19 and 20: LIST OF FIGURES (Continued) 4.2 Fil
Page 21 and 22: LIST OF FIGURES (Continued) 4.43 SE
Page 23 and 24: 2 of transistors on a chip would co
Page 25 and 26: 4 Typically, light beams do the etc
Page 27 and 28: Having the technology to transfer t
Page 29 and 30: 8 capacitance of the wire. It may s
Page 31 and 32: 10 side of the chip to the other. O
Page 33 and 34: metal/oxide/semiconductor integrate
Page 35: 14 properties of the film obtained
Page 39 and 40: 18 Figure 1.1 Scheme to show the tr
Page 41 and 42: 20 the low-pressure operation. Dry
Page 43 and 44: 22 • Reaction: The surface cataly
Page 45 and 46: 24 If the deposition process is lim
Page 47 and 48: 26 1.2 Types of CVD Process As ment
Page 49 and 50: 28 Lowering the gas pressure by abo
Page 51 and 52: 30 purity and density, controllable
Page 53 and 54: 32 to block alkali ions. All films
Page 55 and 56: 34 Some of the attractive propertie
Page 57 and 58: 36 1.5 Refractory Materials Ceramic
Page 59 and 60: 38 deposited and then a conducting
Page 61 and 62: 40 Table 1.7 Physical properties of
Page 63 and 64: 42 In Chapter 2, a review of litera
Page 65 and 66: Material Melting Temperature (°C)
Page 67 and 68: 46 The reaction involving BCl 3 for
Page 69 and 70: 48 B2H6 + 2NH3 = 2BN + 6H2 Rand et
Page 71 and 72: 50 ammonia at 250° - 600°C in an
Page 73 and 74: 52 2.3.1 Synthesis by CVD and LPCVD
Page 75 and 76: 54 temperature range of 700-1300 K
Page 77 and 78: 56 The refractive index of c-BN was
Page 79 and 80: 58 the problem to hydrogen content
Page 81 and 82: 60 Many researchers 70,69,82 have s
Page 83 and 84: 62 BN film coatings are useful to i
Page 85 and 86: 64 2.5.1 Dielectric Thin Films With
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66 A family of thermally stable, lo
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68 suggested that the there is a ch
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70 a heavily dependent on process c
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72 Typically thin beryllium or poly
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Figure 2.2 Trends in ULSI miniaturi
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76 Figure 2.3 Basic SCALPEL princip
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78 50 nanometers and smaller. The r
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80 A large number of materials have
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82 2.7 Aim and Scope of the Present
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84 jacket maintained the temperatur
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86 Figure 3.2 Schematic diagram of
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88 contamination and hence requires
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90 known reaction chamber volume. T
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92 all the experiments. The boat wa
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94 limited by sample surface and a
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96 3.5.6 Film Stress Stress develop
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98 3.5.7 X-Ray Diffraction (XRD) A
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100 where hγ , Eg(opt) and K 1 den
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102 technique. However the films we
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104 same film surface. Such measure
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106 the device, an electrical conta
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108 Figure 3.5 Process flow diagram
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110 samples. The recombination-gene
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112 3.7.2 Characterization of B-N-C
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114 In all the experiments, films d
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116 operating in the mass transfer
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118 variation in the NH3/TEAB flow
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120 mode, and a small peak close to
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122 infrared absorption spectra, no
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124 increasing the NH3/TEAB flow ra
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126 tensile behavior with increase
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128 material with the electrons jum
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130 while at a constant temperature
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132 4.4.6 Electrical Characterizati
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134 4.4.6.2 Investigation of LPCVD
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136 Figure 4.17 C-V curve shift alo
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138 Figure 4.18 Capacitance-Voltage
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140 Thus by knowing the refractive
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142 rate of 40 sccm, as the Power w
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144 4.4.7.2 Characterization of B-N
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146 the reactant species in eq. 4.2
Page 169 and 170:
148 Figure 4.25 Variation of Film C
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150 Figure 4.27 Plot of growth rate
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152 4.5.3 Rate Equation Knowing the
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154 4.5.4 Reaction Mechanism In the
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156 high TiC14 coverage. ΘTiC13 ca
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158 Figure 4.30 shows a typical XPS
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160 degraded. Hence, films with thi
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162 Figure 4.35 Variation in film d
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164 Figure 4.37 Variation in film r
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166 emittance increased; the transm
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Figure 4.41 SEM micrograph of TiN d
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Figure 4.4 3 SEM micrograph of TiN
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172 Orientation (hid) Table 4.1 Com
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174 carried out under the same proc
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176 was not in a compound form. It
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REFERENCES 1. R. Turton. 1995. The
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180 36. W. Kern and V. S. Ban, "Che
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182 74. L. Imhoff, A. Bouteville, a
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