Characterisation and Control of Defects in Semiconductors

Cover
Title
Copyright
Contents
Preface
1 Characterizing electrically active defects by transient capacitance spectroscopy
    1.1 Introduction
    1.2 Characteristics of electrically active defect levels
    1.3 Junction spectroscopic techniques for characterizing deep-level defects
        1.3.1 Deep-level transient spectroscopy
        1.3.2 Variations of capacitance spectroscopic techniques
        1.3.3 Deep-level optical spectroscopy
    1.4 Examples: characterizing electrically active defects in semiconductors
        1.4.1 Irradiation-induced defect complexes and vacancy migration in silicon
        1.4.2 Electrically active defects in zinc oxide and the involvement of hydrogen
    1.5 Extending junction spectroscopic techniques beyond traditional methodology
    1.6 Conclusions
    Acknowledgments
    References
2 Luminescence from point defects in wide-bandgap, direct-gap semiconductors
    2.1 Introduction
    2.2 Types of transitions related to photoluminescence
    2.3 Phenomenological models
        2.3.1 Rate equations model
        2.3.2 Configuration-coordinate model
        2.3.3 Diagonal transitions between localized states
        2.3.4 Summary
    2.4 Experiment: photoluminescence from defects
        2.4.1 Radiative defects in GaN
        2.4.2 Defect-related photoluminescence in other wide bandgaps
        2.4.3 Summary
    2.5 Conclusions and outlook
    References
3 Vibrational spectroscopy
    3.1 Theory
        3.1.1 Units
        3.1.2 Linear chain
        3.1.3 Defect vibrational modes
        3.1.4 Anharmonic potential
        3.1.5 IR activity
        3.1.6 Number of atoms
        3.1.7 Infrared absorption
        3.1.8 Linewidth and temperature dependence
        3.1.9 Wave functions and symmetry
        3.1.10 Anharmonic coupling
        3.1.11 Raman scattering
    3.2 Experiment
        3.2.1 Raman spectroscopy
        3.2.2 Fourier transform infrared spectroscopy
        3.2.3 IR pump–probe
        3.2.4 Applied stress
    3.3 Examples
        3.3.1 Interstitial oxygen
        3.3.2 Impurities in GaAs
        3.3.3 Resonant interaction in AlSb
        3.3.4 Impurities in CdTe
        3.3.5 Hydrogen in silicon
        3.3.6 Impurity-hydrogen pairs: trends
        3.3.7 MgH complex in GaN
        3.3.8 NH complex in ZnO
        3.3.9 Hydrogen donors in oxide semiconductors
        3.3.10 Vacancy-hydrogen complexes
        3.3.11 Hydrogen in strontium titanate
        3.3.12 Hydrogen molecules
        3.3.13 From LVM to phonon
    3.4 Summary and outlook
    Acknowledgements
    References
4 Magnetic resonance methods
    4.1 Electron spin resonance spectroscopies
        4.1.1 What is EPR used for?
        4.1.2 Spin Hamiltonian formalism
        4.1.3 Hyperfine interactions
        4.1.4 Resonance
        4.1.5 Transition probability: relaxation phenomena
        4.1.6 Experimental setup
        4.1.7 Electron nuclear double resonance
        4.1.8 Pulsed spectroscopies
        4.1.9 Optically detected magnetic resonance, electrically detected magnetic resonance
    4.2 Illustrative examples: structural and chemical control
        4.2.1 The SiC/oxide interface defects
        4.2.2 The N dumbbell in GaN
    4.3 Examples: electrical and optical activities
        4.3.1 P-Type doping of GaN
        4.3.2 Origin of the residual conductivity of Ga2O3
        4.3.3 SiC defects as quantum bits
    4.4 Summary and outlook
    References
5 The role of muons in semiconductor research
    5.1 Introduction
    5.2 Muon spin research (μSR): the techniques
        5.2.1 General principles
        5.2.2 Polarisation functions
        5.2.3 Transverse field μSR
        5.2.4 Longitudinal field μSR
        5.2.5 Zero-field μSR
        5.2.6 Resonance-based μSR techniques
        5.2.7 Low-energy muons (LEM or LE-μSR)
        5.2.8 Illumination and muon spectroscopy of excited states
    5.3 Putting muons to use in semiconductors
        5.3.1 Muonium states
        5.3.2 Identifying muonium centres
        5.3.3 Processes and dynamics involving muonium centres
        5.3.4 Measuring donor and acceptor levels
        5.3.5 Effects of carrier concentrations
    5.4 Select examples of μSR contributions to the field
        5.4.1 Group-IV
        5.4.2 Group III–V
        5.4.3 Group II–VI
        5.4.4 Group II–IV–V2 chalcopyrites
        5.4.5 Oxides
    5.5 Final thoughts
    Acknowledgements
    References
6 Positron annihilation spectroscopy, experimental and theoretical aspects
    6.1 Introduction
    6.2 Positrons in crystalline semiconductors
        6.2.1 Positrons obtained from radioactive sources
        6.2.2 Slow monoenergetic positron beams for thin-layer studies
        6.2.3 Positron thermalization and diffusion
        6.2.4 Positron trapping
        6.2.5 The kinetic trapping model and positron lifetime spectroscopy
    6.3 Doppler broadening techniques
        6.3.1 Doppler broadening spectroscopy
        6.3.2 Coincidence Doppler broadening spectroscopy
        6.3.3 Supporting theory for defect identification
    6.4 Temperature-dependent measurements in narrow bandgap semiconductors
        6.4.1 Vacancy annealing in Ge
        6.4.2 Positron traps in low temperature irradiated GaSb
    6.5 Acceptor-like defects in wide bandgap semiconductors
        6.5.1 Cation vacancies and acceptor impurities in GaN and ZnO
        6.5.2 Cation and oxygen vacancies in metal oxides
    6.6 Summary and outlook
    References
7 First principles methods for defects: state-of-the-art and emerging approaches
    7.1 Defect levels
    7.2 Defect thermochemistry
        7.2.1 Defect formation enthalpy
        7.2.2 Phase stabilities and chemical potential space
        7.2.3 Defect formation enthalpy diagrams
        7.2.4 Configuration coordinate diagrams and optical excitation
        7.2.5 Defect equilibria and carrier concentrations
    7.3 Sources of uncertainty in defect formation energy calculations
    7.4 Total energies using first principles electronic structure calculations
        7.4.1 Overview and many-particle Schro¨dinger equation
        7.4.2 Hartree–Fock
        7.4.3 Density functional theory
        7.4.4 Emerging approaches—quantum Monte Carlo
    7.5 Achieving higher accuracy with density functional theory and other approaches
        7.5.1 Observations
        7.5.2 Generalized Koopman’s theorem
        7.5.3 LDA+U and PBE+U
        7.5.4 Green’s function approaches: the GW method
        7.5.5 Hybrid functionals
        7.5.6 Fitted chemical potentials
    7.6 Finite size effects
        7.6.1 Charged defects
        7.6.2 Band filling for shallow defects
    7.7 Recent examples
        7.7.1 Mg and other possible acceptors in GaN
        7.7.2 Oxygen vacancies and other defects in metal oxides
        7.7.3 Transition metal impurities
        7.7.4 Defect clustering and aggregation
    7.8 Summary and outlook
    References
8 Microscopy of defects in semiconductors
    8.1 Introduction
    8.2 Basic principles of the microscopy techniques
        8.2.1 Scanning probe microscopy
        8.2.2 Scanning electron microscopy
        8.2.3 Transmission electron microscopy
    8.3 Examples of the application of microscopy to semiconductor materials
        8.3.1 Dislocation densities and Burgers vectors in GaN
        8.3.2 Imaging of the impact of dislocations on materials properties
        8.3.3 A multi-microscopy example: structure, properties and interactions of dislocations in InGaN
        8.3.4 Imaging defects in 2D materials
    8.4 Conclusions and outlook
    Acknowledgements
    References
9 Three-dimensional atomic-scale investigation of defects in semiconductors by atom probe tomography
    9.1 Introduction
    9.2 Atom probe tomography
        9.2.1 Generalities and history
        9.2.2 Principles and performances
        9.2.3 APT versus SIMS
    9.3 Three-dimensional defects
        9.3.1 Nanocrystals, quantum dots
        9.3.2 Impurity clusters
    9.4 Two-dimensional defects
        9.4.1 Segregation to stacking faults
        9.4.2 Stacking faults in heterostructures
        9.4.3 Intergranular segregation of dopants in silicon
        9.4.4 Segregation of dopants to gate interfaces in MOSFET transistors
    9.5 One-dimensional defects
    9.6 Point defects
        9.6.1 Three-dimensional field ion microscopy
        9.6.2 In situ photoluminescence
    9.7 Conclusion
    Acknowledgements
    References
10 Ion-beam modification of semiconductors
    10.1 Introduction
    10.2 Theoretical and experimental background
        10.2.1 Theory of ion stopping and energy deposition
        10.2.2 Basics of ion implantation experiments
    10.3 Damage production and annealing
        10.3.1 Low-fluence primary damage
        10.3.2 Defect migration and interaction
        10.3.3 High-fluence damage overlap and amorphization
        10.3.4 Recrystallization of amorphous state
        10.3.5 Defect evolution during recrystallization and dopant activation
    10.4 Ripple formation on semiconductors
        10.4.1 Experimental background
        10.4.2 Theoretical models
    10.5 Time-resolved experiments to probe defect evolution
        10.5.1 Dynamic annealing
        10.5.2 Traditional dose-rate effect experiments
        10.5.3 Pulsed-ion-beam method
        10.5.4 Comparison of radiation defect dynamics in different semiconductors
    10.6 Conclusions
    Acknowledgments
    References
11 Characterizing defects with ion beam analysis and channeling techniques
    11.1 Tutorial
        11.1.1 Ion beam analysis
        11.1.2 Channeling techniques
    11.2 Examples
        11.2.1 Damage in semiconductors
        11.2.2 Lattice location of dopants
    11.3 Outlook
        11.3.1 Technical developments
        11.3.2 Emerging applications
    References
Index