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

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in terms of stopping power and stopping cross section respectively. Knowledge of the stopping power allows the overall slowing down to be described in a quantitative way. It therefore enables calculation of the range. Rearranging equation 2.13 and integrating from the maximum energy E0 to zero yields the total path length, R(E), of the ion: dE ∫ 0 + dx e E0 R ( E) = or ( E) ( dE ) ( dE ) 2.4.2 Simulation of ion implantation (using SRIM) dx n 1 dE R = N ∫ (2.14) S + 27 E0 ( E) S ( E) 0 n e Several computer simulation codes have been developed to calculate parameters such as the range and straggling of implanted ions. The Stopping and Range of Ions in Matter (SRIM) (3) is a group of programs which calculate the stopping and range of energetic ions into matter using a fit to a full quantum mechanical treatment of ion-atom collisions. The most comprehensive of these programs is the Transport of Ions in Matter (TRIM). The TRIM simulation code is widely used for simulating the effects of ion implantation and has been useful within this study to compare theory to the experimental depth profiles obtained from MEIS. Because of the statistical nature of the paths of implanted ions simulations TRIM uses Monte Carlo methods and a binary collision algorithm to calculate the ion trajectories of many implanted ions. It will accept complex targets made of compound materials, and calculate the final 3D distribution of implanted ions and also all kinetic phenomena associated with the ion’s energy loss: target damage, sputtering, ionisation and phonon production. As an example a simulation of the paths of twenty implanted As and B ions into Si with an implant energy of 3 keV, is shown in Figure 2.5 a) and b) respectively. The shallower implantation and smaller amount of straggling seen with As compared to B is due to the higher nuclear stopping power. TRIM works on the basis of an amorphous matrix.
Figure 2.5 Results of TRIM simulations showing the trajectories of 20 a) 3 keV As ions and b) 3 keV B ions, implanted into Si. 2.4.3 Channelling of the ions As mentioned previously in relation to the inelastic energy loss, in a crystal there are large open channels (25). If implantation is carried out along an axis it can be possible for a small fraction of the ions to be channelled to considerably greater depths. Screening prevents large angle scattering. For ion implantation this is undesirable as shallow junctions are required. Often pre-amorphisation or implantation off axis is carried out to avoid channelling. Channelling is exploited in the MEIS analysis technique to study damaged layers and this is described in section 4.2.1.6. References 1 N. Bohr, Phil. Mag. 25 10 (1913) 2 N. Bohr, Phil. Mag., 30 581 (1915) 3 Ziegler, J. F. SRIM – The Stopping and Range of Ions in Matter. (Accessed 07/04) 4 N. Bohr, Kgl. Dansk. Vid. Selsk. Mat. Fys. Medd. 18, No 8, 1948. 5 O. B. Firsov, Sov. Phys. JETP 6, 1958, 534. 6 G. Moliere, Z. Naturforsch. 2a, 1947, 133. 7 L. Lindhard, V. Nielsen, M. Scharff, Det Kong. Dan. Viden. Selskab. Mat. Fys. Medd. 36, 1968, 10. 8 J. F. Ziegler, J. P. Biersack, and U. Littmark, The Stopping and Range of Ions in Solids (Pergamon Press, New York, 1985). 9 Van der Veen, J.F., Surf. Sci. Rep., 5, Nos. 5/6, 1985. 28
Page 1 and 2: Damage formation and annealing stud
Page 3 and 4: 3.2.2.6 Other models 40 3.2.3 Other
Page 5 and 6: Chapter 7 Interaction between Xe, F
Page 7 and 8: List of Figures Figure 1.1 a) Schem
Page 9 and 10: Figure 4.13 Variation in the kinema
Page 11 and 12: Figure 6.10 MEIS energy spectra for
Page 13 and 14: Figure 7.8 Combined MEIS Xe depth p
Page 15 and 16: Abbreviations and Symbols a/c amorp
Page 17 and 18: 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: dE/dx (eV/Ang) 125 100 75 50 25 0 2
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 and 70: Category I defects are produced whe
Page 71 and 72: thermal annealing (600 - 700 °C an
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
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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.
Page 103 and 104:
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
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Inelastic energy loss (eV/Ang) 32 2
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iterative procedure is carried out
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Yield (couts per 5µC) 300 250 200
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SIMS experiments were also carried
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MEIS, using the scattering conditio
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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
Page 171 and 172:
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
Page 191 and 192:
20 L. Capello, T. H. Metzger, M. We
Page 193 and 194:
egarding B profiles relevant to the
Page 195 and 196:
Page 197 and 198:
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
Page 207 and 208:
21 M. Anderle, M. Bersani, D. Giube
Page 209 and 210:
stopped at depths beyond the observ
Page 211:
the role of each individual element
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