Kinetic and Strain-Induced Self-Organization of SiGe ...

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8 CHAPTER 1. SILICON-GERMANIUM MATERIAL SYSTEM DA double steps have a by far subordinate abundance. Fig. 1.5 (after [8]) depicts a schematic model of the most common step types on Si(001) showing SB and DB steps in their rebonded configuration. [8]. 1.2.2 Step Types in Different Miscut Angle Regimes For small miscuts below 1 ◦ only mono-atomic steps with a height of 0.136 nm (i.e. aSi/4) are found. Both single-step types are present but reveal a different nature. Whereas the SA-steps are rather straight and smooth, the SB-steps appear rugged. There are many SA- kinks in SB-steps and few SB-kinks in SA-steps as it costs less energy to create an SA step segment [11]. Fig. 1.6 [12] shows an STM image (∼ 350 ˚A × 350 ˚A) of such a typical vicinal Si(001) surface with a low miscut of 0.66 ◦ along [110]. Equally spaced A- (orange) and B-terraces (violet) can be clearly discerned. The regular (2×1)-reconstruction is revealed as dimer-rows spanning along the 〈110〉-directions over the terraces with an altered orientation parallel (A-terrace) and perpendicular (B-terrace) to the step-edges. Thus the B-terraces are defined by rugged SB-steps at the lower side and rather straight SA-steps at the upper boundary. Figure 1.6: STM image (∼ 350 ˚A × 350 ˚A) of a vicinal Si(001) surface with a miscut of 0.66 ◦ along [110] revealing equally spaced A- (orange) and B-terraces (violet). The regular (2×1)-reconstruction is revealed as dimer-rows spanning along the 〈110〉-directions over the terraces with an altered orientation parallel (A-terrace) and perpendicular (B-terrace) to the step-edges. Thus the B-terraces are defined by rugged SB-steps at the lower side and rather straight SA-steps at the upper boundary. [12] � Source: SiGe STM stepped-surface.jpg
1.3. ELECTRONIC PROPERTIES 9 Monoatomic height steps separate surface stress domains due to the anisotropic in-plane stress linked to the dimerization of the terraces [13, 14]. Especially for low miscuts (< 0.03 ◦ ) a slightly wavy surface morphology is established which shrinks the size of stress domains by introducing reverse steps and increasing the step density over the necessary value to accommodate the miscut [15, 16, 17]. Therefore the local miscut partially exceeds the overall ”averaged” substrate miscut. For miscut angles exceeding 1 ◦ along [110] the evolution of double-atomic steps sets in and the fraction of these mainly DB-steps is increased with increasing miscut (between 1 ◦ and 10 ◦ ) [18]. The formation of the surface structure is a complex interplay of strain fields associated with step rebonding, step-step interactions, and energy differences between an SA-SB step pair and rebonded DB-steps [19]. In the current work the main emphasis was directed to vicinal Si(001) substrates with a miscut of 4 ◦ along [110]. Hence the average terrace lengths can be estimated with 1.94 nm (3.88 nm) assuming purely mono-atomic (di-atomic) surface steps. [8]. 1.3 Electronic Properties 1.3.1 Band Structure Silicon is like Germanium and Carbon (Diamond) an indirect semiconductor, which means that the lowest minima of the conduction band and the highest maxima in the valence band are not located at the same position in � k-space. In Fig. 1.7 [12] the Brillouin zone of the diamond lattice structure is depicted. Figure 1.7: Brillouin zone of the fcc lattice [12]. � Source: SiGe Brillouin-zone.jpg
Page 1: J O H A N N E S K E P L E R U N I V
Page 4 and 5: ii PREFACE Kurzfassung Eine kinetis
Page 6 and 7: iv PREFACE
Page 8 and 9: vi CONTENTS 2.1.3 Growth-Modes . .
Page 10 and 11: viii CONTENTS B General Physical Da
Page 13 and 14: Chapter 1 Silicon-Germanium Materia
Page 15 and 16: 1.1. STRUCTURAL PROPERTIES 5 Figure
Page 17: 1.2. VICINAL SI(001) 7 Vicinal subs
Page 21 and 22: 1.3. ELECTRONIC PROPERTIES 11 Silic
Page 23 and 24: 1.4. SILICON GERMANIUM ALLOYS (SI1
Page 25 and 26: Chapter 2 Molecular Beam Epitaxy (M
Page 27 and 28: 2.1. MBE-GROWTH 17 hit the substrat
Page 29 and 30: 2.1. MBE-GROWTH 19 Figure 2.3: The
Page 31 and 32: 2.2. CLEANING PROCEDURE 21 rameter
Page 33 and 34: 2.2. CLEANING PROCEDURE 23 H2SO4 :
Page 35 and 36: 2.3. MBE-SYSTEM 25 Figure 2.7: All-
Page 37 and 38: 2.3. MBE-SYSTEM 27 Figure 2.9: Sche
Page 39 and 40: Chapter 3 Methods of Investigation
Page 41 and 42: 3.2. SCANNING ELECTRON MICROSCOPY (
Page 43 and 44: 3.3. ATOMIC FORCE MICROSCOPY (AFM)
Page 51: Part II Main Research 41
Page 54 and 55: 44 CHAPTER 4. SELF-ORGANIZED GROWTH
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58 CHAPTER 5. SELF-ORGANIZED GROWTH
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86 CHAPTER 6. P-MODULATION DOPING A
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100 CHAPTER 6. P-MODULATION DOPING
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Chapter 7 Transient-Enhanced Si Dif
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7.3. EXPERIMENTAL RESULTS 117 > 100
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7.3. EXPERIMENTAL RESULTS 119 Figur
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7.4. DETAILED CHARACTERIZATION AND
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7.4. DETAILED CHARACTERIZATION AND
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Chapter 8 Germanium Source Reconstr
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Figure 8.2: Elevated front-view of
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water lines. Figure 8.4: Photograph
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Figure 8.7: Part 2 of final constru
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Appendix A Calibration and Characte
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A.1. CALIBRATIONS 135 Figure A.1: X
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A.1. CALIBRATIONS 137 Figure A.3: N
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A.2. PHOTOLUMINESCENCE 139 Sample 1
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A.2. PHOTOLUMINESCENCE 141 Figure A
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A.2. PHOTOLUMINESCENCE 143 Figure A
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Appendix B General Physical Data B.
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Bibliography [1] Herbert Lichtenber
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BIBLIOGRAPHY 149 [42] M. B. Prince,
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BIBLIOGRAPHY 151 [85] J. Zhu, K. Br
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BIBLIOGRAPHY 153 [130] C. S. Peng,
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BIBLIOGRAPHY 155 [174] G. Medeiros-
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BIBLIOGRAPHY 157 [214] G. Bastard,
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Postface Curriculum Vitae ⋄ ∗ 1
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POSTFACE 161 � D. Gruber, D. Pach
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POSTFACE 163 Abbreviations AFM Atom
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Kinetic and Strain-Induced Self-Organization of SiGe ...

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