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

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Yield (counts per 5µC nm/s Yield (counts per 5µC 400 300 200 100 1 0.1 0.01 120 100 80 60 40 20 Si profile 3 keV As 2E15 ions/cm 2 SPE Regrowth Rate As profile 0 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Depth (nm) Figure 6.10 and the top of Figure 6.11 shows that the implant produces an ~ 11 nm amorphous layer. The regrowth rate at 600 °C is slow enough to capture various intermediate stages of regrowth for the different durations. The regrowth starts at the amorphous crystalline (a/c) interface and proceeds to the surface in a layer-by-layer fashion as evidenced by the half height of the back edge of the Si peak moving to progressively shallower depths with increasing annealing duration. The slopes of the 141 Random as-impl 600 o C 5s 600 o C 10s 600 o C 20s 600 o C 30s 600 o C 40s 600 o C 60s 600 o C 120s 6x10 22 5x10 22 4x10 22 3x10 22 2x10 22 1x10 22 0 3x10 21 2x10 21 1x10 21 Figure 6.11 MEIS Si depth profiles (top), As depth profiles (bottom) and approximate regrowth rates (centre). concentration (at/cm 3 ) concentration (at/cm 3 )
ack edges of the Si peaks are very similar for all samples. As mentioned previously this slope is mainly caused by a combination of the energy resolution of the MEIS system and energy straggling. Their similarity supports the layer-by-layer regrowth since deviations from this behaviour would result in a change in width of the a/c interface and hence the slope of the back edge. This aspect of the MEIS spectra and SPER will be discussed in more detail in section 6.4 in relation to the regrowth of SOI wafers. The depths of the a/c interfaces are tabulated in Table 6.3. The behaviour of the As can also be observed very clearly with this series of samples. The As profiles, in the bottom of Figure 6.11, show the original As peak disappearing from “view” of the analysing beam and the As becoming substitutional. The segregation of excess As can be clearly observed as discussed before. Both of these effects are seen most clearly with the longer anneal durations. A comparison of the Si and the As profiles shows that they are closely related. After any of the anneals, the depth of the half height of the back edge of the Si peak, representing the a/c interface, has moved in a similar fashion to the half height of the back edge of the As peaks. The As no longer visible has taken up substitutional positions after the a/c interface has swept past. The amount of As visible is shown in Table 6.3 and is also expressed as a percentage of the implant. For the sample annealed for 120s the regrowth appears to be almost complete. The amount of visible As is also low at 40%. This value is close to the values observed for high anneal temperatures (< 1000 °C) seen in section 6.2.3. However the As peak is not quite as sharp as those observed for high temperature spike anneals and appears to have a “tail” at around 3-5 nm, suggesting imperfect regrowth in this region. Figure 6.10 shows that the variation in oxide thickness with anneal temperature is comparatively small in this experimental series. 142
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Damage formation and annealing stud
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3.2.2.6 Other models 40 3.2.3 Other
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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
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Chapter 7 5 M. Werner, J.A. van den
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terminal (Vg), current cannot flow
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This is an approximate average leve
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the active channel, adjacent to the
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To continue to improve devices ther
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produces a device quality regrown l
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technique of channelling Rutherford
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22 J.S Williams. Solid Phase Recrys
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and the probability of scattering t
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importance for many atomic collisio
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M1, V0, E0 Figure 2.2 Elastic scatt
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2.3.1 Models for inelastic energy l
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dE/dx (ev/Ang) 10 1 Inelastic Energ
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dE/dx (eV/Ang) 125 100 75 50 25 0 2
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Figure 2.5 Results of TRIM simulati
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Chapter 3 Damage and Annealing proc
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the Si/SiO2 interface, consuming th
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On the basis that by creating an in
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Figure 3.4 Structure of crystalline
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a Si atom will suffer little angula
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3.2.2.5 Homogeneous model (Critical
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Sputtering and atomic mixing play a
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and is approximately 25 times faste
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elevant dopants later. For equal co
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nearest neighbour distance (52). By
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Category I defects are produced whe
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thermal annealing (600 - 700 °C an
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Figure 3.11 Relationship between im
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defect pairs due to Coulomb attract
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⎛ 〈 C ⎞ ⎛ ⎞ I 〉 〈 C V
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27 R.D. Goldberg, J. S. Williams, a
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67 H. Bracht. Diffusion Mechanism a
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Hall effect measurements were carri
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energy than one scattered from an a
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epresents a small improvement over
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(dE/dx)out multiplied by the path l
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they are small compared to the diff
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ackscattering (27). This fact forms
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Figure 4.7 a) Plot of a Gaussian di
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similar to the width of the error f
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UP Ion Beam SPIN Rotation Sample Sc
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Kinematic factor (K) 1.0 0.8 0.6 0.
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Figure 4.14 Illustration of the dou
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4.2.2.4 Interpretation of spectra A
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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
Page 121 and 122: an N2/O2 environment to maintain an
Page 123 and 124: 38 M. Anderle, M. Barozzi, M. Bersa
Page 125 and 126: damage evolution behaviour observed
Page 127 and 128: Yield (counts per 5 µC) 250 200 15
Page 129 and 130: essentially a “zero dose” profi
Page 131 and 132: no longer “visible” in MEIS has
Page 133 and 134: yield (cts / 5µC) 500 400 300 200
Page 135 and 136: 5.4 Conclusion MEIS analysis with a
Page 137 and 138: Chapter 6 Annealing studies 6.1 Int
Page 139 and 140: 6.2.2.2 Results and Discussion Figu
Page 141 and 142: theory predictions and X-ray fluore
Page 143 and 144: implantation conditions are those u
Page 145 and 146: a) b) c) Yield (counts per 5 µC) Y
Page 147 and 148: greater than MEIS. SIMS is not sens
Page 149 and 150: attributed to the interference betw
Page 151 and 152: The as-implanted sample, with a bro
Page 153 and 154: a) b) Yield (counts per 5 µC) Yiel
Page 155 and 156: interface, as evidenced by the high
Page 157 and 158: duration, is observed. MEIS results
Page 159: Yield (counts per 5µC) 500 400 300
Page 163 and 164: underneath the SiO2 layer, iii) it
Page 165 and 166: R s (Ω/sq) 950 900 850 800 750 60
Page 167 and 168: As concentration (at/cm 3 ) 1E22 1E
Page 169 and 170: R s (Ω/sq) 950 900 850 800 750 70
Page 171 and 172: Following annealing it was observed
Page 173 and 174: ∆a/a (x 10 -3 ) 4,0 epi550 3,5 3,
Page 175 and 176: Yield (counts per 5 uC) 350 300 250
Page 177 and 178: (FWHM). Concomitantly, As in the re
Page 181 and 182: The higher temperature anneals carr
Page 183 and 184: ecomes steeper for the sample annea
Page 185 and 186: Figure 6.28 Schematic illustrations
Page 187 and 188: and the 2D picture in Figure 6.31b)
Page 189 and 190: 6.5 Conclusion In summary, in this
Page 191 and 192: 20 L. Capello, T. H. Metzger, M. We
Page 193 and 194: egarding B profiles relevant to the
Page 197 and 198: TRIM AU 0.04 0.03 0.02 0.01 TRIM si
Page 199 and 200: a) F profile PAI 3 keV BF2 b) F pro
Page 201 and 202: Yield (counts per 5 µC) 20 15 10 5
Page 203 and 204: the corresponding PAI sample, yield
Page 205 and 206: amorphous matrix, (16) i.e. local c
Page 207 and 208: 21 M. Anderle, M. Bersani, D. Giube
Page 209 and 210: stopped at depths beyond the observ
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the role of each individual element
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