Analysis of the extended defects in 3C-SiC.pdf - Nelson Mandela ...

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70 7.2.1 Crystal Structure and the SiC/Si Interface Fig. 7.1. Bright field TEM micrograph of the Si/SiC interfac. B = [011], g = ≥ 0. Inserted are SAD patterns taken from the bulk of the SiC and over the interface _ 11 1, s Fig. 7.1. shows a bright-field TEM micrograph of the SiC/Si interface (in figure caption). The beam direction B is [011] with diffraction vector g = [ 111] deviation parameter s ≥ 0. The inserts are selected area diffraction (SAD) patterns taken of the areas indicated and are rotated to reflect the correct directions as in the micrograph since there is a rotational relationship between diffraction and image planes in the TEM. This rotation relationship has been tabulated for the TEM for various magnifications and is used for the correction. In this particular case the rotation could also be found easily due to the direction of growth of the 3C-SiC being known. The left hand SAD pattern is consistent with the 3C-SiC phase with beam direction B = [011] and lattice parameter 4.35 Å. The camera length of the TEM was calibrated using the Si substrate as reference. This diffraction pattern (right hand) corresponds to the superposition of the two sets of diffraction patterns of the Si and SiC, with the pattern containing the shorter set of reciprocal lattice vectors being that of the SiC and the other that of the Si. The following procedure was followed. _ and
Fig. 7.2. Simulated diffraction pattern of the [011] zone axis of 3C-SiC. 71 Fig. 7.2 shows an indexed simulated diffraction pattern of the [011] zone axis of 3C- SiC. From diffraction theory it is known that the diffraction patterns obey the following relation (Hirsch et al. (1965)), L Rd hkl where λ is the electron wavelength, L the camera length, R the distance from the transmitted or central diffraction spot to the diffraction spot in question and dhkl the interplanar spacing given by (Hirsch et al. (1965)), d hkl h 2 a k 2 l 2 with a the lattice parameter of the material and h,k,l the Miller indices of the diffraction vector used. Using these relations the lattice parameter of a crystal can be determined from a diffraction pattern provided the camera constant λL is known. R
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Analysis of the Extended Defects in
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My sincere thanks to the following
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OPSOMMING Hierdie dissertasie hande
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4.2.5. Two-Beam Scattering Matrix 4
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Dedicated to my wife and parents
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SUMMARY The dissertation focuses on
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CONTENTS Chapter 1: INTRODUCTION 1
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1 CHAPTER ONE INTRODUCTION Silicon
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2.1. Introduction 3 CHAPTER TWO OVE
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2.2.2 The Zinc-Blende Structure 5 T
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2.3 Point Defects, Defect Migration
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v m Em vm0 exp( ) (2.2) kT 9 wher
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11 explained and the concept of par
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13 Straight dislocations furthermor
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2.5 Partial Dislocations and Slip 1
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17 Fig. 2.13. The geometrical setup
Page 33 and 34: 19 extrinsic stacking faults are th
Page 35 and 36: 2.8 Twinning 21 Twinning is a proce
Page 37 and 38: 23 Fig. 2.20. The process of vacanc
Page 39 and 40: S n Td (3.2) 25 and is also referr
Page 41 and 42: 27 where a = a0(Z1 2/3 + Z2 2/3 ) -
Page 43 and 44: 29 Using this expression, curves of
Page 45 and 46: 31 As stated previously hard-sphere
Page 47 and 48: 33 where A is the atomic weight. Th
Page 49 and 50: 35 a vacancy dislocation loop if th
Page 51 and 52: 37 Fig. 4.1. (a) A wave incident on
Page 53 and 54: 39 Consider Fig. 4.2 which illustra
Page 55 and 56: 41 V0 is the mean inner potential o
Page 57 and 58: 43 beam left-hand side g' = 0 g' =
Page 59 and 60: 45 In addition another set of indep
Page 61 and 62: 47 When this is incorporated into t
Page 63 and 64: S ( s , z ) e T i Se ( / 0 )
Page 65 and 66: z0 z2 . xn cos and (4.47) D 1 proj
Page 67 and 68: 5.1 Introduction 53 CHAPTER FIVE LI
Page 69 and 70: 55 different orientations. The inte
Page 71 and 72: 57 Furthermore Pirouz et al. (1987)
Page 73 and 74: 59 intersection of the fault, the f
Page 75 and 76: 61 each nuclei because of the low s
Page 77 and 78: 63 (2000) found that subsequent ann
Page 79 and 80: 6.3.1 Ion Range and Defect Producti
Page 81 and 82: 67 Fig. 6.3. Total number of displa
Page 83: 7.1 Introduction 69 CHAPTER SEVEN R
Page 87 and 88: 73 Fig. 7.3. A HRTEM image of the S
Page 89 and 90: 75 Fig. 7.5. The stacking fault sel
Page 91 and 92: (Si/ni) 2 0.000018 0.000016 0.00001
Page 93 and 94: 79 may be concluded that the initia
Page 95 and 96: 81 Fig. 7.11. Bright field TEM micr
Page 97 and 98: 83 Fig. 7.12 which was obtained by
Page 99 and 100: 85 Fig. 7.13. Bright-field TEM micr
Page 101 and 102: 87 (a) (b) Fig. 7.15. The (a) exper
Page 103 and 104: 89 In the following paragraphs the
Page 105 and 106: Fig. 7.18. CBED pattern taken of th
Page 107 and 108: 93 Table 7.5. The measured paramete
Page 109 and 110: 7.4.2 Results 95 Fig. 7.22. Bright-
Page 111 and 112: 97 Twin platelets on {111} planes
Page 113 and 114: 99 REFERENCES Blumenau, A.T., Jones
Page 115 and 116: 101 Hull, D., Bacon, D.J. : (1984)
Page 117: 103 Smith, D.J., Jepps, N.W. and Pa
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