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

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(a) (b) 66 Fig. 6.2. (a) Si and C vacancies produced per unit distance in 3C-SiC using displacement energies of 35 eV and 20 eV respectively (Heinisch et al.); (b) Si and C vacancies produced per unit distance in 3C-SiC using displacement energies of 93 eV and 16.3 eV respectively (Vladimirov et al.) SRIM gives the number of vacancies produced per ion for the two sets of displacement energies to be 13.2 and 10.1 respectively. It is also evident from Fig. 6.2. that the number of Si vacancies is always less than that of the C due to its displacement energy being higher. In the case of Fig. 6.2 (b) the anisotropy is very high with an order of magnitude difference in the numbers produced. Fig. 6.3. shows a plot of the number of displaced atoms per unit distance per incoming ion for the displacement energies used by Heinsich et al. (2004).
67 Fig. 6.3. Total number of displacements produced in the 3C-SiC per incoming ion per Angstrom. If an area around the peak of the projected range is selected, as indicated on the above figure, an estimate of the total number of displacements per unit volume around the damage region can be obtained for the dose used by assuming that the number of displacements per incoming ion per angstrom to be constant over this region. Multiplying it by the dose and dividing it by the volume which in this case is a disc with thickness of the area selected and diameter of 1 cm. The number of displacements per cm 3 is then found to be 9.5×10 21 in the damage region. This is about an order of magnitude lower than the concentration of atoms per unit volume in SiC which is 9.6×10 22 . 6.4 Annealing Procedure After the proton implantation two sets of samples were sent to the University of the Witwatersrand for annealing at 1300 °C and 1600 °C for 1 hr. The annealing was done in vacuum.
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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
Page 29 and 30: 2.5 Partial Dislocations and Slip 1
Page 31 and 32: 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: 6.3.1 Ion Range and Defect Producti
Page 83 and 84: 7.1 Introduction 69 CHAPTER SEVEN R
Page 85 and 86: Fig. 7.2. Simulated diffraction pat
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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Analysis of the extended defects in 3C-SiC.pdf - Nelson Mandela ...

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