Contents

• Contents
• List of Tables
• List of Figures
• Introduction
• Theoretical Background
  • The Hartree Equations
  • Hartree-Fock Theory
    • Discussion
  • Thomas-Fermi Theory
  • Density Functional Theory
  • The local density approximation
    • Parameterising the correlation energy
  • Kohn-Sham Theory
    • Discussion
  • Pseudopotentials
    • Generating pseudopotentials
  • Other theoretical approaches
    • Semi-Empirical Hartree Fock
      • CNDO
    • Interatomic Potentials
    • Use of the Musgrave-Pople potential in this work
• AIMPRO methodology
  • Expanding the Wavefunction
  • Approximation to the charge density
    • Spin averaged $\tilde{E}_{xc}$ and improvements to the approximations
    • Spin polarised exchange correlation
    • Summary so far
    • Matrix Formalism
  • Self-consistency
    • Fermi statistics and `level smearing'
  • Evaluation of Forces
  • Structural Optimisation
  • Calculation of Vibrational Modes
    • Induced Dipole Moments
  • Discussion of the methods used in AIMPRO
    • Density functional theory / Local Density Approximation
    • Real space
    • Clusters
    • H termination
    • Gaussian orbitals
    • Bond centred Gaussian fitting functions
  • Application of AIMPRO to the oxygen in silicon problem
• Hydrogen in III-V materials
  • Background
    • Electrical effects and the role of Fe
    • Group II impurities in InP
  • Method
  • Pure InP
  • Hydrogenated Vacancy Centres
  • Passivation of Group II Impurities
    • Varying acceptor and host - InP, GaAs, Be and Mg
  • Conclusions
• Vacancy - Oxygen complexes in Silicon
  • Introduction
    • The VO Centre
    • The formation of VO<sub>2</sub>
    • Higher order VO<sub>n</sub> defects
  • Method and Results
    • The VO Defect
    • The VO<sub>2</sub> Defect
    • Alternatives to VO<sub>2</sub> - the V<sub>2</sub>O Defect
    • The VO<sub>3</sub> Defect
    • The OV-O<sub>i</sub> pre-cursor to the VO<sub>2</sub> centre
  • Discussion
• Oxygen-Oxygen defects
  • Background
    • Interstitial Oxygen
    • The oxygen dimer
    • The 1012 cm<sup>-1</sup> LVM
  • Method
    • Orthogonality Constraints
    • Constraining Bond Lengths
  • Interstitial oxygen
  • The oxygen dimer
    • The symmetric dimer
    • The split dimer
    • Dimer Migration
  • Dimer Formation
    • Experimental Evidence
  • Dimer interaction with other defects
  • Trimer formation
    • Theoretical Results
  • Conclusions
• Nitrogen-Oxygen defects in Silicon
  • Method
  • Background
  • The N<sub>i</sub> defect
  • N<sub>2i</sub>O - The dominant N-O defect in silicon
    • Experimental Work
    • Theoretical Work
  • N<sub>i</sub>O<sub>i</sub> - pre-cursor to STDs and the NNO
    • Alternative Models - NNOO
  • Conclusions and Discussion
• Shallow Thermal Donors in Silicon
  • Background
  • Method
  • N<sub>i</sub>O<sub>2i</sub> - The N-O Shallow Thermal Donor
  • Other potential STD models
    • (N<sub>2i</sub>)<sub>n</sub>-O<sub>i</sub> - Suezawa's model
    • Substitutional Nitrogen
    • Bistable NNO structures
  • Formation processes for N-O defects
  • (C-H) based shallow thermal donors
    • (C-H)<sub>i</sub>O<sub>2i</sub>
  • Identification of NL10
  • (CH)<sub>i</sub>-O<sub>4i</sub> and the `pop-out' mechanism
    • Experimental Background
    • Results
  • Summary of (CH)-O_ni defects and further work
  • The Wonderbra Mechanism--
    Deep to Shallow Donor Conversion
    • Discussion and Future Applications
• Thermal Donors in Si
  • Experimental data on the thermal donors
    • EPR and ENDOR
    • Stress-induced alignment experiments
    • FTIR
    • Other information
    • Previous theoretical models
  • Results
  • The 4 O di-y-lid thermal donor
    • Discussion of the di-y-lid model
    • Hydrogen passivation
  • Other models
    • The 5O_i Thermal Donor
    • Alternative 4O_i structures
      • The `flanked square' structure
      • The di-square structure
    • Three O atom TD species
      • Snyder-Stavola model
      • Partially dissociated 3O model
    • Six oxygen atom TD species
  • Al in the di-y-lid core - NL10(Al)?
  • Y-lids - Tri-valent oxygen
  • The role of silicon self-interstitials
  • Earlier Thermal Donors - O_i to TD3
    • Di-y-lid is TD2 - a serial process
    • Di-y-lid is TD3 - a parallel process
    • General discussion of early stages of TD formation
    • Early Stages - Summary
  • Later Thermal Donors - TD3 and beyond
    • 1D thermal donors
    • 2/3D thermal donors
    • Later TDs - Summary and Conclusion
• Conclusions and Further Work
• References