Damage formation and annealing studies of low energy ion implants ...

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Figure 3.8 The relationship between the damage density distribution (solid lines) and amorphisation threshold (dashed line) leading to the different categories of defect. From (36). 3.4.2 End of Range defects and their evolution upon annealing Defects formed in the EOR region beyond the original amorphous / crystalline interface (Category II defects), and specifically their evolution, can play an important role in the diffusion of dopant atoms. Five important types of EOR defects are described here, all of which arise because of an excess of interstitials. These defects evolve through a ripening process which is driven by the reduced formation energy of larger defects. Smaller clusters dissociate while the larger defects attract the released interstitials and remain stable up to high temperatures. The effect on diffusion is discussed in section 3.5. Immediately following implantation and in the early stage of annealing, most of the excess interstitials are stored as di-interstitials (54). These can grow during moderate 51
thermal annealing (600 – 700 °C and form small aggregates of Si interstitials, with the most stable “magic” clusters being made up of 4 and 8 atoms (55). For longer anneal times and higher temperatures, the excess interstitials condense into extended defects (56). This category of defects consist of {113}’s, perfect dislocation loops (PDL’s) and faulted dislocation loops (FDL’s) and TEM images of each are shown in Figure 3.9. Figure 3.9 TEM images of defects present in the EOR damage area of ion implanted Si. These are clusters, {113}s, PDLs, and FDLs. From (56). {113} rod like defects are formed from smaller clusters and can become visible in a TEM from lengths of 2 nm (57). The {113} defects are bundles of rows of Si diinterstitials that lie on {113} planes and which are elongated along directions and consist of condensates of interstitials forming five and seven – membered rings (58). This atomic arrangement provides a way to insert planes of self interstitials without dangling bonds (58). They have a constant width of 4 nm. Once {113} defects are formed, further annealing can make the larger {113}’s grow in size at the expense of the smaller ones, thereby reducing the density of {113}’s. Dislocation loops form in the most densely packed crystal planes for reason of energy minimisation. Typically the loops consist of circular extra {111} planes of Si interstitials with the lattice elongated along directions. Perfect dislocation loops 52
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Damage formation and annealing stud
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3.2.2.6 Other models 40 3.2.3 Other
Page 5 and 6:
Chapter 7 Interaction between Xe, F
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List of Figures Figure 1.1 a) Schem
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Figure 4.13 Variation in the kinema
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Figure 6.10 MEIS energy spectra for
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Figure 7.8 Combined MEIS Xe depth p
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Abbreviations and Symbols a/c amorp
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Abstract The work described in this
Page 19 and 20: Chapter 7 5 M. Werner, J.A. van den
Page 21 and 22: terminal (Vg), current cannot flow
Page 23 and 24: This is an approximate average leve
Page 25 and 26: the active channel, adjacent to the
Page 27 and 28: To continue to improve devices ther
Page 29 and 30: produces a device quality regrown l
Page 31 and 32: technique of channelling Rutherford
Page 33 and 34: 22 J.S Williams. Solid Phase Recrys
Page 35 and 36: and the probability of scattering t
Page 37 and 38: importance for many atomic collisio
Page 39 and 40: M1, V0, E0 Figure 2.2 Elastic scatt
Page 41 and 42: 2.3.1 Models for inelastic energy l
Page 43 and 44: dE/dx (ev/Ang) 10 1 Inelastic Energ
Page 45 and 46: dE/dx (eV/Ang) 125 100 75 50 25 0 2
Page 47 and 48: Figure 2.5 Results of TRIM simulati
Page 49 and 50: Chapter 3 Damage and Annealing proc
Page 51 and 52: the Si/SiO2 interface, consuming th
Page 53 and 54: On the basis that by creating an in
Page 55 and 56: Figure 3.4 Structure of crystalline
Page 57 and 58: a Si atom will suffer little angula
Page 59 and 60: 3.2.2.5 Homogeneous model (Critical
Page 61 and 62: Sputtering and atomic mixing play a
Page 63 and 64: and is approximately 25 times faste
Page 65 and 66: elevant dopants later. For equal co
Page 67 and 68: nearest neighbour distance (52). By
Page 69: Category I defects are produced whe
Page 73 and 74: Figure 3.11 Relationship between im
Page 75 and 76: defect pairs due to Coulomb attract
Page 77 and 78: ⎛ 〈 C ⎞ ⎛ ⎞ I 〉 〈 C V
Page 79 and 80: 27 R.D. Goldberg, J. S. Williams, a
Page 81 and 82: 67 H. Bracht. Diffusion Mechanism a
Page 83 and 84: Hall effect measurements were carri
Page 85 and 86: energy than one scattered from an a
Page 87 and 88: epresents a small improvement over
Page 89 and 90: (dE/dx)out multiplied by the path l
Page 91 and 92: they are small compared to the diff
Page 93 and 94: ackscattering (27). This fact forms
Page 95 and 96: Figure 4.7 a) Plot of a Gaussian di
Page 97 and 98: similar to the width of the error f
Page 99 and 100: UP Ion Beam SPIN Rotation Sample Sc
Page 101 and 102: Kinematic factor (K) 1.0 0.8 0.6 0.
Page 103 and 104: Figure 4.14 Illustration of the dou
Page 105 and 106: 4.2.2.4 Interpretation of spectra A
Page 107 and 108: with are comparatively small, ~ 0.5
Page 109 and 110: Inelastic energy loss (eV/Ang) 32 2
Page 111 and 112: iterative procedure is carried out
Page 113 and 114: Yield (couts per 5µC) 300 250 200
Page 115 and 116: SIMS experiments were also carried
Page 117 and 118: MEIS, using the scattering conditio
Page 119 and 120: 4.5 Sample production Samples have
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an N2/O2 environment to maintain an
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38 M. Anderle, M. Barozzi, M. Bersa
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damage evolution behaviour observed
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Yield (counts per 5 µC) 250 200 15
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essentially a “zero dose” profi
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no longer “visible” in MEIS has
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yield (cts / 5µC) 500 400 300 200
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5.4 Conclusion MEIS analysis with a
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Chapter 6 Annealing studies 6.1 Int
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6.2.2.2 Results and Discussion Figu
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theory predictions and X-ray fluore
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implantation conditions are those u
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a) b) c) Yield (counts per 5 µC) Y
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greater than MEIS. SIMS is not sens
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attributed to the interference betw
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The as-implanted sample, with a bro
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a) b) Yield (counts per 5 µC) Yiel
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interface, as evidenced by the high
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duration, is observed. MEIS results
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Yield (counts per 5µC) 500 400 300
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ack edges of the Si peaks are very
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underneath the SiO2 layer, iii) it
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R s (Ω/sq) 950 900 850 800 750 60
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As concentration (at/cm 3 ) 1E22 1E
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R s (Ω/sq) 950 900 850 800 750 70
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Following annealing it was observed
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∆a/a (x 10 -3 ) 4,0 epi550 3,5 3,
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Yield (counts per 5 uC) 350 300 250
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(FWHM). Concomitantly, As in the re
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The higher temperature anneals carr
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ecomes steeper for the sample annea
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Figure 6.28 Schematic illustrations
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and the 2D picture in Figure 6.31b)
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6.5 Conclusion In summary, in this
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20 L. Capello, T. H. Metzger, M. We
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egarding B profiles relevant to the
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TRIM AU 0.04 0.03 0.02 0.01 TRIM si
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a) F profile PAI 3 keV BF2 b) F pro
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Yield (counts per 5 µC) 20 15 10 5
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the corresponding PAI sample, yield
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amorphous matrix, (16) i.e. local c
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21 M. Anderle, M. Bersani, D. Giube
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stopped at depths beyond the observ
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the role of each individual element
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