8f01390bebef7c6073dbd8b327758945c8271df3
[lectures/latex.git] / posic / talks / dpg_2008.tex
1 \pdfoutput=0
2 \documentclass[landscape,semhelv]{seminar}
3
4 \usepackage{verbatim}
5 \usepackage[german]{babel}
6 \usepackage[latin1]{inputenc}
7 \usepackage[T1]{fontenc}
8 \usepackage{amsmath}
9 \usepackage{latexsym}
10 \usepackage{ae}
11
12 \usepackage{calc}               % Simple computations with LaTeX variables
13 \usepackage{caption}            % Improved captions
14 \usepackage{fancybox}           % To have several backgrounds
15
16 \usepackage{fancyhdr}           % Headers and footers definitions
17 \usepackage{fancyvrb}           % Fancy verbatim environments
18 \usepackage{pstricks}           % PSTricks with the standard color package
19
20 \usepackage{pstricks}
21 \usepackage{pst-node}
22
23 \usepackage{epic}
24 \usepackage{eepic}
25
26 \usepackage{graphicx}
27 \graphicspath{{../img/}}
28
29 \usepackage[setpagesize=false]{hyperref}
30
31 \usepackage{semcolor}
32 \usepackage{semlayer}           % Seminar overlays
33 \usepackage{slidesec}           % Seminar sections and list of slides
34
35 \input{seminar.bug}             % Official bugs corrections
36 \input{seminar.bg2}             % Unofficial bugs corrections
37
38 \articlemag{1}
39
40 \special{landscape}
41
42 \begin{document}
43
44 \extraslideheight{10in}
45 \slideframe{none}
46
47 \pagestyle{empty}
48
49 % specify width and height
50 \slidewidth 27.7cm 
51 \slideheight 19.1cm 
52
53 % shift it into visual area properly
54 \def\slideleftmargin{3.3cm}
55 \def\slidetopmargin{0.6cm}
56
57 \newcommand{\ham}{\mathcal{H}}
58 \newcommand{\pot}{\mathcal{V}}
59 \newcommand{\foo}{\mathcal{U}}
60 \newcommand{\vir}{\mathcal{W}}
61
62 % itemize level ii
63 \renewcommand\labelitemii{{\color{gray}$\bullet$}}
64
65 % topic
66
67 \begin{slide}
68 \begin{center}
69
70  \vspace{16pt}
71
72  {\LARGE\bf
73   Molecular dynamics simulation study\\
74   of the silicon carbide precipitation process
75  }
76
77  \vspace{24pt}
78
79  \textsc{\small \underline{F. Zirkelbach}$^1$, J. K. N. Lindner$^1$,
80          K. Nordlund$^2$, B. Stritzker$^1$}\\
81
82  \vspace{32pt}
83
84  \begin{minipage}{2.0cm}
85   \begin{center}
86   \includegraphics[height=1.6cm]{uni-logo.eps}
87   \end{center}
88  \end{minipage}
89  \begin{minipage}{8.0cm}
90   \begin{center}
91    {\footnotesize
92     $^1$ Experimentalphysik IV, Institut f"ur Physik,\\
93          Universit"at Augsburg, Universit"atsstr. 1,\\
94          D-86135 Augsburg, Germany
95    }
96   \end{center}
97  \end{minipage}
98  \begin{minipage}{2.3cm}
99   \begin{center}
100   \includegraphics[height=1.5cm]{Lehrstuhl-Logo.eps}
101   \end{center}
102  \end{minipage}
103
104  \vspace{16pt}
105
106  \begin{minipage}{4.0cm}
107   \begin{center}
108   \includegraphics[height=1.6cm]{logo_eng.eps}
109   \end{center}
110  \end{minipage}
111  \begin{minipage}{8.0cm}
112   \begin{center}
113   {\footnotesize
114    $^2$ Accelerator Laboratory, Department of Physical Sciences,\\
115    University of Helsinki, Pietari Kalmink. 2,\\
116    00014 Helsinki, Finland
117   }
118   \end{center}
119  \end{minipage}
120 \end{center}
121 \end{slide}
122
123 % contents
124
125 \begin{slide}
126
127  \begin{center}
128  {\bf
129   Molecular dynamics simulation study\\
130   of the silicon carbide precipitation process
131  }
132  \end{center}
133
134  \vspace{16pt}
135
136  {\large\bf
137   Outline
138  }
139
140  \vspace{16pt}
141
142  \begin{itemize}
143   \item Motivation / Introduction
144   \item Molecular dynamics simulation details
145         \begin{itemize}
146          \item Integrator, potential, ensemble control
147          \item Simulation sequence
148         \end{itemize}
149   \item Simulation results
150         \begin{itemize}
151          \item Interstitials in silicon
152          \item SiC-precipitation experiments
153         \end{itemize}
154   \item Conclusion / Outlook
155  \end{itemize}
156 \end{slide}
157
158 % start of contents
159
160 \begin{slide}
161
162  {\large\bf
163   Motivation / Introduction
164  }
165
166  \vspace{16pt}
167
168  Reasons for investigating C in Si:
169
170  \begin{itemize}
171   \item 3C-SiC wide band gap semiconductor formation
172   \item Strained Si (no precipitation wanted!)
173  \end{itemize}
174
175  \vspace{16pt}
176
177  Si / 3C-SiC facts:
178
179  \begin{minipage}{8cm}
180  \begin{itemize}
181   \item Unit cell:
182         \begin{itemize}
183          \item {\color{yellow}fcc} $+$
184          \item {\color{gray}fcc shifted $1/4$ of volume diagonal}
185         \end{itemize}
186   \item Lattice constants: $4a_{Si}\approx5a_{SiC}$
187   \item Silicon density: 
188         \[
189         \frac{n_{SiC}}{n_{Si}}=
190         \frac{4/a_{SiC}^3}{8/a_{Si}^3}=
191         \frac{5^3}{2\cdot4^3}={\color{cyan}97,66}\,\%
192         \]
193  \end{itemize}
194  \end{minipage}
195  \hspace{8pt}
196  \begin{minipage}{4cm}
197  \includegraphics[width=4cm]{sic_unit_cell.eps}
198  \end{minipage}
199
200 \end{slide}
201
202  \small
203 \begin{slide}
204
205  {\large\bf
206   Motivation / Introduction
207  }
208
209  \small
210  \vspace{6pt}
211
212  Supposed conversion mechanism of heavily carbon doped Si into SiC:
213
214  \vspace{8pt}
215
216  \begin{minipage}{3.8cm}
217  \includegraphics[width=3.7cm]{sic_prec_seq_01.eps}
218  \end{minipage}
219  \hspace{0.6cm}
220  \begin{minipage}{3.8cm}
221  \includegraphics[width=3.7cm]{sic_prec_seq_02.eps}
222  \end{minipage}
223  \hspace{0.6cm}
224  \begin{minipage}{3.8cm}
225  \includegraphics[width=3.7cm]{sic_prec_seq_03.eps}
226  \end{minipage}
227
228  \vspace{8pt}
229
230  \begin{minipage}{3.8cm}
231  Formation of C-Si dumbbells on regular c-Si lattice sites
232  \end{minipage}
233  \hspace{0.6cm}
234  \begin{minipage}{3.8cm}
235  Agglomeration into large clusters (embryos)\\
236  \end{minipage}
237  \hspace{0.6cm}
238  \begin{minipage}{3.8cm}
239  Precipitation of 3C-SiC + Creation of interstitials\\
240  \end{minipage}
241
242  \vspace{12pt}
243
244  Experimentally observed:
245  \begin{itemize}
246   \item Minimal diameter of precipitation: 4 - 5 nm
247   \item (hkl)-planes identical for Si and SiC
248  \end{itemize}
249
250 \end{slide}
251
252 \begin{slide}
253
254  {\large\bf
255   Simulation details
256  }
257
258  \vspace{12pt}
259
260  MD basics:
261  \begin{itemize}
262   \item Microscopic description of N particle system
263   \item Analytical interaction potential
264   \item Hamilton's equations of motion as propagation rule\\
265         in 6N-dimensional phase space
266   \item Observables obtained by time average
267  \end{itemize}
268
269  \vspace{12pt}
270
271  Application details:
272  \begin{itemize}
273   \item Integrator: Velocity Verlet, timestep: $1\, fs$
274   \item Ensemble control: NVT, Berendsen thermostat, $\tau=100.0$
275   \item Potential: Tersoff-like bond order potential\\
276         \[
277         E = \frac{1}{2} \sum_{i \neq j} \pot_{ij}, \quad
278         \pot_{ij} = f_C(r_{ij}) \left[ f_R(r_{ij}) + b_{ij} f_A(r_{ij}) \right]
279         \]
280         \begin{center}
281         {\scriptsize P. Erhart und K. Albe. Phys. Rev. B 71 (2005) 035211}
282         \end{center}
283  \end{itemize}
284
285  \begin{picture}(0,0)(-240,-70)
286   \includegraphics[width=5cm]{tersoff_angle.eps} 
287  \end{picture}
288
289 \end{slide}
290
291 \begin{slide}
292
293  {\large\bf
294   Simulation details
295  }
296
297  \vspace{20pt}
298
299  Interstitial experiments:
300
301  \vspace{12pt}
302
303  \begin{itemize}
304   \item Initial configuration: $9\times9\times9$ unit cells Si
305   \item Periodic boundary conditions
306   \item $T=0 \, K$
307   \item Insertion of Si / C atom at
308         \begin{itemize}
309          \item $(0,0,0)$ $\rightarrow$ {\color{red}tetrahedral}
310          \item $(-1/8,-1/8,1/8)$ $\rightarrow$ {\color{green}hexagonal}
311          \item $(-1/8,-1/8,-1/4)$, $(-1/4,-1/4,-1/4)$\\
312                $\rightarrow$ {\color{yellow}110 dumbbell}
313          \item random positions (critical distance check)
314         \end{itemize}
315   \item Relaxation time: $2\, ps$
316   \item Optional heating-up 
317  \end{itemize}
318
319  \begin{picture}(0,0)(-210,-45)
320   \includegraphics[width=6cm]{unit_cell.eps}
321  \end{picture}
322
323 \end{slide}
324
325 \begin{slide}
326
327  {\large\bf
328   Simulation details
329  }
330
331  \small
332
333  SiC precipitation experiments:
334
335  \begin{pspicture}(0,0)(12,8)
336   % nodes
337   \rput(4.5,6.5){\rnode{init}{\psframebox{\parbox{7cm}{
338    \begin{itemize}
339     \item Initial configuration: $31\times31\times31$ unit cells Si
340     \item Periodic boundary conditions
341     \item $T=450\, ^{\circ}C$
342     \item Equilibration of $E_{kin}$ and $E_{pot}$ for $600\, fs$
343    \end{itemize}
344   }}}}
345   \rput(4.5,4.5){\rnode{tc1}{\psframebox[fillstyle=solid,fillcolor=red]{
346                              $T=450\pm 1\, ^{\circ}C$}}}
347   \rput(7,3.5){\rnode{insert}{\psframebox[fillstyle=solid,fillcolor=red]{
348                               \parbox{3cm}{
349                               Insertion of 10 atoms\\
350                               at random positions}}}}
351   \rput(2,3.5){\rnode{adj1}{\psframebox[fillstyle=solid,fillcolor=red]{
352                             \parbox{3.5cm}{
353                             Adjusting temperature\\
354                             for another $100\, fs$}}}}
355   \rput(7,2.5){\rnode{nc}{\psframebox[fillstyle=solid,fillcolor=red]{
356                           $N_{atoms}=6000$}}}
357   \rput(4.5,2){\rnode{tc2}{\psframebox[fillstyle=solid,fillcolor=cyan]{
358                            $T=T_{set}$}}}
359   \rput(7,1){\rnode{td}{\psframebox[fillstyle=solid,fillcolor=cyan]{
360                         $T_{set}:=T_{set}-1\, ^{\circ}C$}}}
361   \rput(2,1){\rnode{adj2}{\psframebox[fillstyle=solid,fillcolor=cyan]{
362                           \parbox{3.5cm}{
363                           Adjusting temperature\\
364                           for another $50\, fs$}}}}
365   \rput(7,0){\rnode{tc3}{\psframebox[fillstyle=solid,fillcolor=cyan]{
366                          $T_{set}=20\, ^{\circ}C$}}}
367   \rput(10,0){\rnode{end}{\psframebox{End}}}
368   % help nodes
369   \rput(7,4.5){\pnode{tc1-h}}
370   \rput(2,4.5){\pnode{tc1-hh}}
371   \rput(4.5,2.5){\pnode{nc-h}}
372   \rput(9,2.5){\pnode{nc-hh}}
373   \rput(9,2){\pnode{tc2-h}}
374   \rput(2,2){\pnode{tc2-hh}}
375   \rput(4.5,0){\pnode{tc3-h}}
376   % direct lines
377   \ncline[]{->}{init}{tc1}
378   \ncline[]{->}{adj1}{tc1}
379   \ncline[]{->}{insert}{nc}
380   \ncline[]{->}{adj2}{tc2}
381   \ncline[]{->}{tc2}{td}
382   \lput*{0}{yes}
383   \ncline[]{->}{td}{tc3}
384   \ncline[]{->}{tc3}{end}
385   \lput*{0}{yes}
386   % lines using help nodes
387   \ncline[]{tc1}{tc1-h}
388   \lput*{0}{yes}
389   \ncline[]{->}{tc1-h}{insert}
390   \ncline[]{tc1}{tc1-hh}
391   \lput*{0}{no}
392   \ncline[]{->}{tc1-hh}{adj1}
393   \ncline[]{nc}{nc-h}
394   \lput*{0}{no}
395   \ncline[]{->}{nc-h}{tc1}
396   \ncline[]{nc}{nc-hh}
397   \ncline[]{-}{nc-hh}{tc2-h}
398   \ncline[]{->}{tc2-h}{tc2}
399   \lput*{0}{yes, {\footnotesize $T_{set}:=450\, ^{\circ}C$}}
400   \ncline[]{tc2}{tc2-hh}
401   \lput*{0}{no}
402   \ncline[]{->}{tc2-hh}{adj2}
403   \ncline[]{tc3}{tc3-h}
404   \lput*{0}{no}
405   \ncline[]{->}{tc3-h}{tc2}
406   % insertion volumes
407   \psframe[fillstyle=solid,fillcolor=white](9.5,1.3)(13.5,5.3)
408   \psframe[fillstyle=solid,fillcolor=lightgray](10,1.8)(13,4.8)
409   \psframe[fillstyle=solid,fillcolor=gray](10.5,2.3)(12.5,4.3)
410   \rput(9.75,3){\pnode{ins1}}
411   \rput(10.25,3.3){\pnode{ins2}}
412   \rput(10.75,3.6){\pnode{ins3}}
413   \ncline[]{-}{insert}{ins1}
414   \ncline[]{-}{insert}{ins2}
415   \ncline[]{-}{insert}{ins3}
416   \psframe[fillstyle=solid,fillcolor=white](9.5,7.6)(13.5,8.1)
417   \psframe[fillstyle=solid,fillcolor=lightgray](9.5,6.8)(13.5,7.3)
418   \psframe[fillstyle=solid,fillcolor=gray](9.5,6)(13.5,6.5)
419   \rput(11.5,7.85){{\tiny Simulation volume:
420                           $31\times31\times31\, a^3_{Si}$}}
421   \rput(11.5,7.05){{\tiny Volume of minimal SiC precipitation}}
422   \rput(11.5,6.25){{\tiny Volume of necessary amount of Si}}
423  \end{pspicture}
424
425 \end{slide}
426
427 \begin{slide}
428
429  {\large\bf
430   Results
431  }
432
433  Si self-interstitial experiments:
434
435  {\footnotesize
436  {\bf Note:}
437  \begin{itemize}
438   \item $r_{cutoff}^{Si-Si}=2.96>\frac{5.43}{2}$
439   \item Bond length near $r_{cutoff} \Rightarrow$ small bond strength
440  \end{itemize}
441  }
442
443  \vspace{8pt}
444
445  \small
446
447  \begin{minipage}[t]{4.0cm}
448  \underline{Tetrahedral}
449  \begin{itemize}
450   \item $E_f=3.41\, eV$
451   \item essentialy tetrahedral\\
452         bonds
453  \end{itemize}
454  \end{minipage}
455  \hspace{0.3cm}
456  \begin{minipage}[t]{4.0cm}
457  \underline{110 dumbbell}
458  \begin{itemize}
459   \item $E_f=4.39\, eV$
460   \item essentially 4 bonds
461  \end{itemize}
462  \end{minipage}
463  \hspace{0.3cm}
464  \begin{minipage}[t]{4.0cm}
465  \underline{Hexagonal}
466  \begin{itemize}
467   \item $E_f^{\star}\approx4.48\, eV$
468   \item unstable!
469  \end{itemize}
470  \end{minipage}
471
472  \vspace{8pt}
473
474  \begin{minipage}[t]{4.3cm}
475  \includegraphics[width=3.8cm]{si_self_int_tetra_0.eps}
476  \end{minipage}
477  \begin{minipage}[t]{4.3cm}
478  \includegraphics[width=3.8cm]{si_self_int_dumbbell_0.eps}
479  \end{minipage}
480  \begin{minipage}[t]{4.3cm}
481  \includegraphics[width=3.8cm]{si_self_int_hexa_0.eps}
482  \begin{center}
483  \href{../video/si_self_int_hexa.avi}{$\rhd$}
484  \end{center}
485  \end{minipage}
486
487 \end{slide}
488
489 \begin{slide}
490
491  {\large\bf
492   Results
493  }
494
495  \vspace{8pt}
496
497  Si self-interstitial \underline{random insertion} experiments:
498
499  \small
500
501  \vspace{8pt}
502
503  \begin{minipage}[t]{4.0cm}
504  \begin{itemize}
505   \item $E_f=3.97\, eV$
506   \item 3 identical weak bonds
507   \item displaced in volume\\ diagonal
508  \end{itemize}
509  \end{minipage}
510  \hspace{0.3cm}
511  \begin{minipage}[t]{4.0cm}
512  \begin{itemize}
513   \item $E_f=3.75\, eV$
514   \item 4 identical weak bonds
515   \item displaced in plane\\ diagonal
516  \end{itemize}
517  \end{minipage}
518  \hspace{0.3cm}
519  \begin{minipage}[t]{4.0cm}
520  \begin{itemize}
521   \item $E_f=3.56\, eV$
522   \item single weak bond
523   \item displaced along\\ $x$-direction
524   \item closest to tetrahedral\\ configuration
525  \end{itemize}
526  \end{minipage}
527
528  \vspace{8pt}
529
530  \begin{minipage}{4.3cm}
531  \includegraphics[width=3.8cm]{si_self_int_rand_397_0.eps}
532  \end{minipage}
533  \begin{minipage}{4.3cm}
534  \includegraphics[width=3.8cm]{si_self_int_rand_375_0.eps}
535  \end{minipage}
536  \begin{minipage}{4.3cm}
537  \includegraphics[width=3.8cm]{si_self_int_rand_356_0.eps}
538  \end{minipage}
539
540  \vspace{8pt}
541
542  \begin{center}
543   {\footnotesize
544    {\bf Note:} Displacements relative to tetrahedral configuration
545   }
546  \end{center}
547
548 \end{slide}
549
550 \begin{slide}
551
552  {\large\bf
553   Results
554  }
555
556  \vspace{8pt}
557
558  Carbon interstitial experiments:
559
560  \vspace{12pt}
561
562  \small
563
564  \begin{minipage}[t]{4.0cm}
565  \underline{Tetrahedral}
566  \begin{itemize}
567   \item $E_f=2.67\, eV$
568   \item tetrahedral bond
569  \end{itemize}
570  \end{minipage}
571  \hspace{0.3cm}
572  \begin{minipage}[t]{4.0cm}
573  \underline{110 dumbbell}
574  \begin{itemize}
575   \item $E_f=1.76\, eV$
576   \item C forms 3 bonds
577  \end{itemize}
578  \end{minipage}
579  \hspace{0.3cm}
580  \begin{minipage}[t]{4.0cm}
581  \underline{Hexagonal}
582  \begin{itemize}
583   \item $E_f^{\star}\approx5.6\, eV$
584   \item unstable!
585  \end{itemize}
586  \end{minipage}
587
588  \vspace{8pt}
589
590  \begin{minipage}[t]{4.3cm}
591  \includegraphics[width=3.8cm]{c_in_si_int_tetra_0.eps}
592  \end{minipage}
593  \begin{minipage}[t]{4.3cm}
594  \includegraphics[width=3.8cm]{c_in_si_int_dumbbell_0.eps}
595  \end{minipage}
596  \begin{minipage}[t]{4.3cm}
597  \includegraphics[width=3.8cm]{c_in_si_int_hexa_0.eps}
598  \begin{center}
599  \href{../video/c_in_si_int_hexa.avi}{$\rhd$}
600  \end{center}
601  \end{minipage}
602
603 \end{slide}
604
605 \begin{slide}
606
607  {\large\bf
608   Results
609  }
610
611  %\vspace{8pt}
612
613  Carbon \underline{random insertion} experiments:
614
615  %\vspace{8pt}
616
617  \footnotesize
618
619  \begin{minipage}[c]{6.3cm}
620   \begin{minipage}{3.4cm}
621    \includegraphics[width=3.3cm]{c_in_si_int_001db_0.eps}
622   \end{minipage}
623   \begin{minipage}{2.5cm}
624    \begin{itemize}
625     \item $E_f=0.47\, eV$
626     \item 001 dumbbell
627    \end{itemize}
628   \end{minipage}
629  \end{minipage}
630  \begin{minipage}[c]{6.3cm}
631   \begin{minipage}{3.4cm}
632    \includegraphics[width=3.3cm]{c_in_si_int_rand_162_0.eps}
633   \end{minipage}
634   \begin{minipage}{2.8cm}
635    \begin{itemize}
636     \item $E_f=1.62\, eV$
637     \item 3 weak + strong bonds
638    \end{itemize}
639   \end{minipage}
640  \end{minipage}
641
642  \begin{minipage}[c]{6.3cm}
643   \begin{minipage}{3.4cm}
644    \includegraphics[width=3.3cm]{c_in_si_int_rand_239_0.eps}
645   \end{minipage}
646   \begin{minipage}{2.5cm}
647    \begin{itemize}
648     \item $E_f=2.39\, eV$
649    \end{itemize}
650    \begin{center}
651     \href{../video/c_in_si_int_rand_239.avi}{$\rhd$}
652    \end{center}
653   \end{minipage}
654  \end{minipage}
655  \begin{minipage}[c]{6.3cm}
656   \begin{minipage}{3.4cm}
657    \includegraphics[width=3.3cm]{c_in_si_int_rand_341_0.eps}
658   \end{minipage}
659   \begin{minipage}{2.8cm}
660    \begin{itemize}
661     \item $E_f=3.41\, eV$
662    \end{itemize}
663    \begin{center}
664     \href{../video/c_in_si_int_rand_341.avi}{$\rhd$}
665    \end{center}
666   \end{minipage}
667  \end{minipage}
668
669  \vspace{4pt}
670
671  \begin{center}
672  {\bf Note:} High probability for 110 dumbbell ($1.76\, eV$) configurations!
673  \end{center}
674
675 \end{slide}
676
677 \begin{slide}
678
679  {\large\bf
680   Results
681  }
682
683  SiC-precipitation experiments:
684
685  \begin{minipage}[t]{6.3cm}
686   %\input{../plot/sic_prec}
687   \includegraphics[width=6.0cm]{../plot/sic_prec_energy.ps}
688   \includegraphics[width=6.0cm]{../plot/sic_prec_temp.ps}
689  \end{minipage}
690  \begin{minipage}[t]{6cm}
691   \includegraphics[width=6.0cm]{../plot/sic_pc.ps}
692   \includegraphics[width=6.0cm]{../plot/sic_prec_pc.ps}
693  \end{minipage}
694
695 \end{slide}
696
697 \begin{slide}
698
699  {\large\bf
700   Conclusion / Outlook
701  }
702
703 \vspace{24pt}
704
705 \begin{itemize}
706  \item Importance of understanding C in Si
707  \item Interstitial configurations in silicon using the Albe potential
708  \item Indication of SiC precipitation
709 \end{itemize}
710
711 \vspace{16pt}
712
713 \begin{itemize}
714  \item Displacement and stress calculations
715  \item Diffusion dependence of temperature and carbon concentration
716  \item Analyzing results of the precipitation simulation runs
717  \item Analyzing self-designed Si/SiC interface
718 \end{itemize}
719
720 \end{slide}
721
722 \end{document}
723