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Silicon Technologies: Ion Implantation and Thermal Treatment

Book Description

The main purpose of this book is to remind new engineers in silicon foundry, the fundamental physical and chemical rules in major Front end treatments: oxidation, epitaxy, ion implantation and impurities diffusion.

Table of Contents

  1. Cover
  2. Title Page
  3. Copyright
  4. Preface
  5. Chapter 1: Silicon and Silicon Carbide Oxidation
    1. 1.1. Introduction
    2. 1.2. Overview of the various oxidation techniques
      1. 1.2.1. General information
        1. 1.2.1.1. Oxidation process
        2. 1.2.1.2. Deposition process
      2. 1.2.2. Most frequently used methods in the semiconductor industry
        1. 1.2.2.1. Thermal oxidation
          1. 1.2.2.1.1. Oxidation under dry oxygen
          2. 1.2.2.1.2. Oxidation under water vapor or wet oxidation
        2. 1.2.2.2. Chemical vapor deposition
          1. 1.2.2.2.1. Low temperature with normal pressure (LTCVD)
          2. 1.2.2.2.2. Low pressure (LPCVD)
          3. 1.2.2.2.3. Plasma enhanced (PECVD)
      3. 1.2.3. Other methods
        1. 1.2.3.1. Anodic oxidation
        2. 1.2.3.2. Oxidation assisted by plasma
          1. 1.2.3.2.1. Discharge with constant current
          2. 1.2.3.2.2. Hot cathode discharge
          3. 1.2.3.2.3. High frequency discharge
        3. 1.2.3.3. Low pressure oxidation under an ultra-high vacuum
        4. 1.2.3.4. High pressure oxidation
    3. 1.3. Some physical properties of silica
      1. 1.3.1. The silica structure
      2. 1.3.2. Three useful parameters of silica
      3. 1.3.3.Transport properties in silica
        1. 1.3.3.1. Diffusion of rare gases in silica
          1. 1.3.3.1.1. Solubility
          2. 1.3.3.1.2. Diffusivity
        2. 1.3.3.2. Molecular diffusion in silica
          1. 1.3.3.2.1. Hydrogen diffusion
          2. 1.3.3.2.2. Water diffusion
          3. 1.3.3.2.3. Oxygen diffusion
    4. 1.4. Equations of atomic transport during oxidation
      1. 1.4.1.Transport equations in the general case
      2. 1.4.2. First approximation: C(x) varies slowly with the depth x
        1. 1.4.2.1. Application to the transport of neutral species in an isotropic environment
        2. 1.4.2.2. Application to the transport of species charged under electric field ε(x)
      3. 1.4.3. Second approximation: ε(x) varies slowly with the depth x
      4. 1.4.4. Applications of the transport equations to thermal and anodic oxidation
        1. 1.4.4.1. Anodic oxidation
        2. 1.4.4.2. Thermal oxidation
    5. 1.5. Is it possible to identify the transport mechanisms taking place during oxidation?
      1. 1.5.1. Identification using isotopic labeling techniques
        1. 1.5.1.1. First hypothesis: silicon is the only mobile species
        2. 1.5.1.2. Second hypothesis: oxygen is the only mobile species
          1. 1.5.1.2.1. Oxygen diffusion without interaction with the silica network
          2. 1.5.1.2.2. Oxygen diffusion with interaction with the silica network
          3. 1.5.1.2.3. Oxygen diffusion by a gradual movement of oxygen atoms of the network
      2. 1.5.2. Important results for the thermal oxidation of silicon under dry O2
        1. 1.5.2.1. Films with thickness higher than 20 nm
        2. 1.5.2.2. Films with thicknesses lower than 10 nm
      3. 1.5.3. Important results for wet thermal oxidation
      4. 1.5.4. Conclusions on the atomic transport mechanisms during silicon thermal oxidation
      5. 1.5.5. Experimental results and conclusions on the transport mechanisms during the anodic oxidation of silicon
      6. 1.5.6. Important experimental results from dry SiC thermal oxidation
    6. 1.6. Transport equations in the case of thermal oxidation
      1. 1.6.1. General information on flux and on growth kinetics
      2. 1.6.2. Flux calculation for neutral mobile species
      3. 1.6.3. Flux calculation for ion mobile species
        1. 1.6.3.1. Case of very thin films (X ≤ 3 nm)
        2. 1.6.3.2. Case of thick films (X >> 3 nm)
    7. 1.7. Deal and Grove theory of thermal oxidation
      1. 1.7.1. Flux calculation
        1. 1.7.1.1. Flux in gas Fg and net flux at the gas/oxide interface F1
        2. 1.7.1.2. Net flux in oxide, F2
        3. 1.7.1.3. Flux at the oxide/silicon interface, F3
      2. 1.7.2. Growth kinetics equations
      3. 1.7.3. Remarks on the fluctuations of the oxidation constants kP and kL
      4. 1.7.4. Determination of the oxidation parameters from experimental results
      5. 1.7.5. Confrontation of the Deal and Grove theory with experimental results
      6. 1.7.6. Conclusions on the Deal and Grove theory
    8. 1.8. Theory of thermal oxidation under water vapor of silicon
      1. 1.8.1. Concentration profiles expected for H2O
      2. 1.8.2. Concentration profiles expected for the OH groups
      3. 1.8.3. Concentration profiles expected for H2
      4. 1.8.4. Concentration profiles expected for H
      5. 1.8.5. Comparison of the expected and the experimental profiles
      6. 1.8.6. Wolters theory
    9. 1.9. Kinetics of growth in O2 for oxide films < 30 nm
      1. 1.9.1. Introduction
      2. 1.9.2. Oxidation models of thin films
      3. 1.9.3. Case of ultra-thin films (< 5 nm)
      4. 1.9.4. On line simulator
      5. 1.9.5. Kinetics and models of SiC oxidation
    10. 1.10. Fluctuations of the oxidation constants under experimental conditions
      1. 1.10.1. Role of the pressure
        1. 1.10.1.1. Wet oxidation
        2. 1.10.1.2. Dry oxidation
      2. 1.10.2. Role of the temperature
        1. 1.10.2.1. Wet oxidation
        2. 1.10.2.2. Dry oxidation
      3. 1.10.3. Role of the crystal direction
        1. 1.10.3.1. Wet oxidation
        2. 1.10.3.2. Dry oxidation
      4. 1.10.4. Role of doping
    11. 1.11. Conclusion
    12. 1.12. Bibliography
  6. Chapter 2: Ion Implantation
    1. 2.1. Introduction
    2. 2.2. Ion implanters
      1. 2.2.1. General description
      2. 2.2.2. Ion sources
      3. 2.2.3. Mass analysis and beam optics
      4. 2.2.4. Current measurement
      5. 2.2.5. Production throughput, temperature control and charge effects
    3. 2.3. Ion range
      1. 2.3.1. Binary collision and stopping power
      2. 2.3.2. Profile of the implanted ions
      3. 2.3.3. Backscattering, surface sputter and channeling
      4. 2.3.4. Implantation through a mask
    4. 2.4. Creation and healing of the defects
      1. 2.4.1. Primary collision and cascade
      2. 2.4.2. Point defects
      3. 2.4.3. Accumulation of damages, amorphization
      4. 2.4.4. Damage healing and dopant activation
    5. 2.5. Applications in traditional technologies and new tendencies
      1. 2.5.1. Common implantations
      2. 2.5.2. Other applications and new tendencies
        1. 2.5.2.1. Gettering
        2. 2.5.2.2. High energy implantation
        3. 2.5.2.3. Ultra-thin junctions
        4. 2.5.2.4. SIMOX and Smart-Cut™
    6. 2.6. Conclusion
    7. 2.7. Bibliography
  7. Chapter 3: Dopant Diffusion: Modeling and Technological Challenges
    1. 3.1. Introduction
    2. 3.2. Diffusion in solids
      1. 3.2.1. General information
        1. 3.2.1.1. Fick’s first law
        2. 3.2.1.2. Generalized flow: drift terms
        3. 3.2.1.3. Fick’s second law and simple profiles calculation
        4. 3.2.1.4. Boltzmann-Matano analysis
      2. 3.2.2. Elementary mechanisms
        1. 3.2.2.1. Atomic mechanisms
        2. 3.2.2.2. Atomic theory of the diffusion coefficient
      3. 3.2.3. Semiconductor specificities
        1. 3.2.3.1. Doping influence
        2. 3.2.3.2. Influence of the induced electric field
    3. 3.3. Dopant diffusion in single-crystal silicon
      1. 3.3.1. Predeposition methods
        1. 3.3.1.1. Predepositionin vapor phase
        2. 3.3.1.2. Deposition in the solid phase
      2. 3.3.2. Main experimental observations
        1. 3.3.2.1. Diffused predepositions in neutral atmosphere
        2. 3.3.2.2. Couplings between impurities
        3. 3.3.2.3. The oxidation influence
      3. 3.3.3. Modeling
        1. 3.3.3.1. “Normal” diffusion
        2. 3.3.3.2. “Anomalous” diffusion: diffusion by pairs
    4. 3.4. Examples of associated engineering problems
      1. 3.4.1. Redistribution of the implanted dopants: transient enhanced diffusion
      2. 3.4.2. Engineering of ultra-thin junctions
        1. 3.4.2.1. Engineering of point defects
        2. 3.4.2.2. Fluorine co-implantation
        3. 3.4.2.3. Carbon co-implantation
      3. 3.4.3. Reverse short channel effect
    5. 3.5. Dopant diffusion in germanium
      1. 3.5.1.Thermal diffusion process
        1. 3.5.1.1. Self-diffusion
        2. 3.5.1.2. Donors diffusion
        3. 3.5.1.3. Boron diffusion
      2. 3.5.2. Implanted dopants and junctions engineering
        1. 3.5.2.1. P+/N junctions
        2. 3.5.2.2. N+/P junctions
    6. 3.6. Conclusion
    7. 3.7. Bibliography
  8. Chapter 4: Epitaxy of Strained Si/Si1-x Gex Heterostructures
    1. 4.1. Introduction
      1. 4.1.1. General introduction
      2. 4.1.2. Chemical vapor deposition from the beginning
        1. 4.1.2.1. Introduction
        2. 4.1.2.2. CVD in general
        3. 4.1.2.3. High temperature conventional Si epitaxy
        4. 4.1.2.4. Low-temperature Si and SiGe epitaxy
        5. 4.1.2.5. Development of CVD equipment
      3. 4.1.3. The Epi Centura epitaxy tool
      4. 4.1.4. Some general concepts of epitaxy
    2. 4.2. Engineering of the pMOSFET transistor channel using pseudomorphic SiGe layers
      1. 4.2.1. Introduction
      2. 4.2.2. Growth kinetics of Si and SiGe in chlorinated chemistry
        1. 4.2.2.1. Growth kinetics of Si in chlorinated chemistry
        2. 4.2.2.2. Growth kinetics of SiGe in chlorinated chemistry
      3. 4.2.3. Transposition on patterned substrates
      4. 4.2.4. pMOS transistors incorporating SiGe layers
    3. 4.3. Engineering of the nMOSFET transistor channel using pseudomorphic Si1-yCy layers; SiGeC diffusion barriers
      1. 4.3.1. Introduction
      2. 4.3.2. Incorporation of C in Si and SiGe
      3. 4.3.3. Si/Si1-yCy/Si stacks for nMOS transistors
      4. 4.3.4. nMOS transistors incorporating Si1-yCy layers or SiGeC diffusion barriers
    4. 4.4. Epitaxy of Si raised sources and drains on ultra-thin SOI substrates
      1. 4.4.1. Introduction
      2. 4.4.2. Problems encountered on ultra-thin SOI substrates
      3. 4.4.3. Method developed in response
    5. 4.5. Epitaxy of recessed and raised SiGe:B sources and drains on ultra-thin SOI and SON substrates
      1. 4.5.1. Introduction
      2. 4.5.2. Growth kinetics and boron doping of SiGe in chlorinated chemistry
      3. 4.5.3. Recessed and raised SiGe:B sources and drains on FD-SOI and SON substrates
    6. 4.6. Virtual SiGe substrates: fabrication of sSOI substrates and of dual c-Ge / t-Si channels
      1. 4.6.1. Introduction
      2. 4.6.2. Growth and structural properties of virtual SiGe substrates
      3. 4.6.3. Growth and structural properties of tensily-strained Si layers on SiGe virtual substrates
      4. 4.6.4. Fabrication of sSOI and XsSOI substrates & transport properties
      5. 4.6.5. c-Ge/t-Si dual channels on Si0.5Ge0.5 virtual substrates
    7. 4.7. Thin or thick layers of pure Ge on Si for nano and opto-electronics
      1. 4.7.1. Introduction
      2. 4.7.2. Structural properties of thick layers of Ge on Si (001) and of GeOI
      3. 4.7.3. Optical and transport properties of thick Ge layers on Si (001) and of GeOI substrates
      4. 4.7.4. Structural and optical properties of Ge islands on Si (001)
    8. 4.8. Devices based on sacrificial layers of SiGe
      1. 4.8.1. Introduction
      2. 4.8.2. Selective HCl etching of SiGe selectively compared to Si
      3. 4.8.3. Localized SOI devices and SON
      4. 4.8.4. Devices based on multi-wires and on multi-channels
    9. 4.9. Conclusions and prospects
      1. 4.9.1. General conclusion
      2. 4.9.2. Prospects
    10. 4.10. Bibliography
  9. List of Authors
  10. Index