D I S S E R T A T I O N


Advanced Modeling of
Strained CMOS Technology


ausgeführt zum Zwecke der Erlangung des akademischen Grades
eines Doktors der technischen Wissenschaften

eingereicht an der Technischen Universität Wien
Fakultät für Elektrotechnik und Informationstechnik
von


Stephan-Enzo Ungersböck


Einsiedlergasse 30/7
1050 Wien, Österreich

Matr. Nr. 9625478
geboren am 8. August 1977 in Wien


Wien, im April 2007

• Kurzfassung
• Abstract
• Danksagung
• Contents
• List of Abbreviations and Acronyms
• List of Symbols
  • Notation
  • Physical Quantities
  • Constants
  
  
• 1. Introduction
• 2. Strain Engineering
  • 2.1 Global Strain Techniques
  • 2.2 Local Strain Techniques
    • 2.2.1 Contact Etch Stop Liner Technique
    • 2.2.2 Stress Memorization
    • 2.2.3 Selective Epitaxial Growth Technique
    • 2.2.4 Stress from Shallow Trench Isolation
  • 2.3 Strain Technologies used in High Volume Production
    • 2.3.1 Hybrid Orientation Technology
  
  
• 3. Strained Bulk Band Structure
  • 3.1 Strain
  • 3.2 Stress
  • 3.3 Stress-Strain Relations
    • 3.3.1 The Miller Index Notation
    • 3.3.2 Strain Resulting from Uniaxial Stress
    • 3.3.3 Strain Resulting from Epitaxy
  • 3.4 Basic Properties of the Diamond Structure
    • 3.4.1 Band Structure of Relaxed Si
  • 3.5 Effect of Strain on Symmetry
    • 3.5.1 Hierarchy of systems
    • 3.5.2 $O_{h}$ symmetry
    • 3.5.3 $D_{4h}$ symmetry
    • 3.5.4 $D_{3d}$ symmetry
    • 3.5.5 $D_{2h}$ symmetry
    • 3.5.6 $C_{2h}$ symmetry
    • 3.5.7 $S_{\mathrm{2}}$ symmetry
  • 3.6 Linear Deformation Potential Theory
    • 3.6.1 Strain-Induced Conduction Band Splitting
    • 3.6.2 Strain-Induced Lifting of Degeneracy at X point
    • 3.6.3 Strain-Induced Valence Band Splitting
  • 3.7 The kp method
    • 3.7.1 Effective Electron Mass in Unstrained Si
    • 3.7.2 Strain Effect on the Si Conduction Band Minimum
  • 3.8 EPM for Arbitrary Strain
    • 3.8.1 The Empirical Pseudopotential Method
    • 3.8.2 Inclusion of Strain
  
  
• 4. Quantum Confinement
  • 4.1 Electron Confinement at the Semiconductor-Oxide Interface
    • 4.1.1 The Si-SiO$_2$ Interface
    • 4.1.2 Substrate Orientation (001)
    • 4.1.3 Substrate Orientation (110)
    • 4.1.4 Substrate Orientation (111)
  • 4.2 Strain Effects
    • 4.2.1 Substrate Orientation (001)
    • 4.2.2 Substrate Orientation (110)
    • 4.2.3 Substrate Orientation (111)
  
  
• 5. Physical Mobility Modeling
  • 5.1 Mobility
  • 5.2 Validity of the Boltzmann Transport Equation
  • 5.3 The Monte Carlo Method
    • 5.3.1 Bulk Scattering Mechanisms
    • 5.3.2 Scattering Mechanisms in the 2DEG
    • 5.3.3 Coupling to the Schrödinger Poisson Solver
  • 5.4 MC Algorithm Including Degeneracy Effects
  
  
• 6. Simulation Results
  • 6.1 Bandstructure Calculations
    • 6.1.1 Strain-Induced Shift of the Conduction Band Minimum
    • 6.1.2 Strain-Induced Change of the Shape of the Conduction Band Edge
    • 6.1.3 Subband Structure
  • 6.2 Bulk Electron Mobility of Strained Si
  • 6.3 Electron Inversion Layer Mobility of Strained Si
    • 6.3.1 Channel Mobility in UTB MOSFETs for (001) and (110) Substrates
    • 6.3.2 Degeneracy Effects on Inversion Layer Mobility
  
  
• 7. Summary and Conclusions
• Bibliography
• Own Publications
• Curriculum Vitae
• About this document ...

E. Ungersboeck: Advanced Modelling Aspects of Modern Strained CMOS Technology