Process Technology for Semiconductor Lasers

1. Introduction.- 1.1 Outline of Semiconductor Laser Theory.- 1.2 Semiconductor Lasers in Opto-electronics.- 1.3 Necessary Technology for Semiconductor Lasers.- 1.4 Brief History of Semiconductor Lasers.- 1.5 Typical Semiconductor Lasers.- 2. Materials for Semiconductor Lasers.- 2.1 III-V Compound Semiconductors.- 2.1.1 Band Structure of III-V Semiconductors.- 2.1.2 Other Characteristics of III-V Compound Semiconductors.- 2.2 Crystals for Visible to Near-Infrared-Wavelength Emission Semiconductor Lasers.- 2.2.1 Importance of Visible to Near-Infrared-Wavelenth Laser Emission.- 2.2.2 Crystal Materials for the Near-Infrared Region.- 2.2.3 Crystal Materials for Visible Laser Emission.- 2.3 Crystals for Semiconductor Lasers with 1-µm and Longer Emission Wavelengths.- 2.3.1 Importance of the 1-µm Emission Wavelength.- 2.3.2 Crystal Materials for the 1-µm Emission Wavelength.- 2.3.3 Longer-Wavelength Materials.- 3. Basic Design of Semiconductor Lasers.- 3.1 Double Heterostructures and Their Design.- 3.1.1 Double Heterostructures.- 3.1.2 Design of Double-Heterostructure Lasers.- 3.1.3 Energy-Band Diagram of DH Lasers.- 3.1.4 Optical Properties of DH Lasers.- a) Step-Index Planar Waveguide.- b) TE Modes.- c) TM Modes.- d) Mode-Confinement Factor.- 3.1.5 Threshold Current of DH Lasers.- 4. Epitaxy of III-V Compound Semiconductors.- 4.1 III-V Substrates for Semiconductor Lasers.- 4.1.1 Necessity of Substrates.- 4.1.2 Substrate Quality Requirements.- 4.2 Bulk Growth Techniques.- 4.3 Heteroepitaxial Techniques.- 4.3.1 Liquid-Phase Epitaxy.- 4.3.2 Vapor-Phase Epitaxy.- 4.3.3 Metalo-Organic Chemical-Vapor Deposition.- 4.3.4 Molecular Beam Epitaxy.- 4.3.5 Chemical Beam Epitaxy.- 5. Liquid Phase Epitaxy and Growth Technology.- 5.1 Outline of an LPE System.- 5.2 Reactors.- 5.2.1 Horizontal Reactor.- 5.2.2 Vertical Reactor.- 5.3 Loading Sub-System.- 5.4 Pump and Exhaust Sub-System.- 5.5 Gas-Flow Sub-System.- 5.6 Heating Sub-System.- 5.7 Maintenance.- 5.7.1 Maintenance of a Graphite Boat.- 5.7.2 Baking of the Reactor.- 5.8 Liquid-Phase Epitaxy.- 5.9 LPE Process.- 5.9.1 GaAlAs/GaAs System.- a) Determination of the Source-Material Quantity.- b) LPE Procedure.- 5.9.2 GaInAsP/InP System.- 5.9.3 Other Materials.- a) Visible-Light Semiconductor Lasers.- b) Longer-Wavelength (? > 2µm) Semiconductor Lasers.- 6. Vapor Phase and Beam Epitaxies.- 6.1 Metal-Organic Chemical Vapor Deposition (MOCVD).- 6.1.1 MOCVD System.- 6.1.2 Example of MOCVD Growth.- a) A Double-Heterostructure Wafer.- b) Semiconductor Multilayer Reflector.- 6.1.3 Characterization.- a) Evaluation of the Nominal Threshold-Current Density.- b) Reflectivity of a Multilayer Bragg Reflector.- 6.2 Molecular-Beam and Chemical-Beam Epitaxy.- 6.2.1 Background.- 6.2.2 Chemical Beam Epitaxial System.- 6.2.3 Preparation for Growth.- 6.2.4 GaAs and InP Growth.- 6.2.5 GaxIn1-xAsyP1-y Growth.- 6.2.6 Doping-Level Control.- 6.2.7 Summary of CBE.- 7. Characterization of Laser Materials.- 7.1 Evaluation of Laser Wafers.- 7.2 Measurement of Lattice Mismatch.- 7.3 Measurement of the Impurity Concentration.- 7.3.1 Four-Point Probe Method.- 7.3.2 Schottky Method.- 7.3.3 Hall Measurement.- 7.4 Photoluminescence.- 7.5 Measurement of the Refractive Index.- 7.6 Misfit Dislocation.- 8. Semiconductor-Laser Devices - Fabrication and Characteristics.- 8.1 Fabrication of Fundamental Laser Devices.- 8.1.1 Broad Contact Lasers.- 8.1.2 Stripe-Geometry Lasers.- 8.2 Current Injection and Contacts.- 8.2.1 Current/Voltage Characteristics.- 8.2.2 Current Injection.- 8.3 Evaluation of the Threshold-Current Density.- 8.4 Gain Bandwidth and Oscillation Spectra.- 8.5 Output and Efficiency of Semiconductor Lasers.- 8.6 Near-Field Pattern and Far-Field Pattern.- 8.7 Temperature Characteristics.- 8.8 Reliability.- 9. Mode-Control Techniques in Semiconductor Lasers.- 9.1 Transverse-Mode Characteristics and the Single-Mode Condition.- 9.1.1 Necessity of Transverse-Mode Stabilization.- 9.1.2 Equivalent Refractive-Index Method.- 9.1.3 Eigenvalue Equation of a Guided Mode.- 9.2 Longitudinal-Mode Control.- 9.3 Burying Epitaxy on Mesas and V-Grooves.- 9.3.1 Structures of Index-Guided Lasers.- 9.3.2 Fabrication of Transverse-Mode-Controlled Structures.- 9.4 Mass-Transport Technique.- 9.5 Selective Meltback Technique.- 9.5.1 Selective Meltback Characteristics.- 9.5.2 Application to an Inner-Stripe Structure.- 9.5.3 Application to BH Stripe Lasers.- 9.6 Overgrowth on Gratings.- 9.7 Growth of Quantum Wells.- 9.8 Growth of Multilayer Bragg Mirrors.- 10. Surface-Emitting Lasers.- 10.1 The Concept of Surf ace-Emitting Lasers.- 10.2 Structure and Characteristics.- 10.2.1 GaInAsP/InP Surface-Emitting Lasers.- 10.2.2 GaAlAs/GaAs SE Lasers.- 10.3 Semiconductor Multi-Layer Structure.- 10.4 Two-Dimensional Arrays.- 10.5 Ultralow-Threshold Devices.- 10.6 Future Prospects.- References.