Optical Characterization of Epitaxial Semiconductor Layers

Transcription

1 Günther Bauer Wolfgang Richter (Eds.) Optical Characterization of Epitaxial Semiconductor Layers With 271 Figures Springer

2 Contents Contributors XV 1 Introduction 1 Günther Bauer, Wolfgang Richter 2 Analysis of Epitaxial Growth 12 Wolfgang Richter, Dietrich Zahn 2.1 Vapour Phase Epitaxy: Basics Gas Phase Diagnostics: Transport Theoretical Considerations Experimental Determination of v and T Measurement of Velocities Measurement of Temperature Gas Phase Diagnostics: Reaction Kinetics Optical Techniques Absorption Spectroscopy Laser Induced Fluorescence Spontaneous Raman Scattering Coherent Anti-Stokes Raman Scattering Other Methods Experimental Results Thermal Decomposition of Precursors Decomposition Products Surface Diagnostics Reflectance Anisotropy Spectroscopy (RAS) Surfaces Under Pregrowth Conditions Surfaces During Growth Surface Photo Absorption (SPA) Infrared Reflection Absorption Spectroscopy (IRRAS) Second Harmonic Generation (SHG) Laser Light Scattering (LLS) Conclusions 67

3 X Contents 3 Spectroscopic Ellipsometry 68 Uwe Rossow, Wolfgang Richter 3.1 Principle of Measurement Null-Ellipsometry Photometrie Eilipsometers Description of Light Polarisation The Jones Formalism Stokes Vectors and Mueller Matrices Rotating Analyser EUipsometer in the Jones Formalism The Effective Dielectric Function <e> Experimental Details Rotating Analyser EUipsometer Photoelastic Modulator EUipsometer Polarisers Calibration Procedures Experimental Limits Angle of Incidence Influence of the Windows Trends and New Developments Interpretation of the Effective Dielectric Function Examples of Dielectric Functions Lineshape Analysis of Optical Gaps Direct Inspection of <e> Single Layers on a Substrate The 3-Phase Model Determination of Layer Properties Ultrathin Layers Inhomogeneous Layers Characteristic Experimental Examples Interband Critical Points Influence of Temperature Influence of Defects: Si Implanted GaAs Oxide Overlayers Size Effects: Microcrystalline Si Semiconductor Heterostructures AlGaAs, GaAsP InP on InGaAs CdS on InP Strained Layers of InGaAs Inhomogeneous Systems: Porous Silicon Layers Ill In-Situ Studies Study of GaAs/AL-Ga^As Interfaces Control of Composition Arsenic Layers on Silicon Multilayer Analysis 121

4 Contents XI 3.5 Sample Related Problems Sample Preparation Multilayer Structures Gradually Varying Composition Anisotropics Quantification of Defects and Strain Depolarisation Summary Raman Spectroscopy 129 Norbert Esser, Jean Geurts 4.1 Theory of Raman Spectroscopy Principles of Raman Spectroscopy Electron-Phonon Interaction Resonance Effects Selection Rules Experimental Setup for Raman Scattering Light Source Raman Spectrometer Multichannel Detector Micro-Raman Spectroscopy In-Situ Experiments Analysis of Lattice Dynamical Properties Crystalline Order Vibrational Modes of Monolayers Structure of Thin Overlayers Strain Orientation Composition and Ordering of Mixed Compounds Detection of Reacted Phases Monitoring of Growth Low-Dimensional Effects Folded Acoustical Phonons Confined Optical Phonons Interface Phonons Analysis of Electronic Properties Electronic Band Structure Impurities Free Carriers Low Dimensional Effects Band Bending at Interfaces Band Bending Determination by Plasmon-LO-Phonon Modes Band Bending Determination by Electric-Field Induced Raman Scattering 195

5 XII Contents 4.6 Summary Far-Infrared Spectroscopy 203 Bernd Harbecke, Bernhard Heinz, Volkmar Offermann, Wolfgang Theiß 5.1 Theoretical Foundations Maxwell's Equations Constitutive Equations and Dispersion Relations Plane Waves in an Isotropic and Homogeneous Medium The Energy Balance Boundary Conditions Coherent and Incoherent Reflection and Transmission of Layered Structures The Dielectric Function e(u) The Susceptibility XPM of Lattice Vibrations The Susceptibility XFC(^) of Free Carriers The Berreman Effect The Free Standing Film (e s = 1) Metal Substrate ( e s > 1) Surface Waves Interpretation of Measured Spectra Fourier Transform Spectroscopy Principle Instrumentation Determination of Layer Thicknesses Simple Evaluation of Fabry-Perot Interferences Thickness Determination by Fourier Transforms Direct Interferogram Analysis Full Numerical Simulation of Reflectance Spectra Determination of Carrier Concentrations Semi-Infinite Samples Multilayers Carrier Concentration Profiles A Fast Evaluation Scheme for Diffusion Profiles Confined Electron Systems Properties of Confined Electrons Spectroscopic Techniques Results Determination of Impurity Concentrations Experimental Impurities in Substrates Substitutional Carbon in Silicon Interstitial Oxygen in Silicon Oxygen Precipitates 267

6 Contents XIII Impurities in Thin Layers Shallow Donors and Acceptors Donors and Acceptors in Bulk Materials Donors and Acceptors in Quantum Wells IR Characterisation of Porous Silicon Layers Effective Medium Theories Examples Summary High Resolution X-Ray Diffraction 287 Alois Krost, Günther Bauer, Joachim Woitok 6.1 Principal Scattering Geometries to 20-Scan and w-scan (Rocking-curve) Double-Crystal Diffraction The 4+1 Crystal Diffractometer Triple-Axis Spectrometer Renninger Scans High-Resolution Multiple-Crystal Multiple-Reflection Diffractometer (HRMCMRD) Kinematical and Dynamical Theory Thickness Dependence of Bragg Reflections Strain Phenomena Strains in Epitaxial Layers Partial Relaxation of Strain Rocking-Curves from Heterostructures Single Heterostructures Composition Gradients Characterisation of Epitaxial Layers Grown Tilted Relative to the Substrates Multilayer Structures Superlattices Ewald Sphere Construction of SL-Diffraction Diagrams Interpretation of the Fine Structure in X-Ray Diffraction Profiles of SL's Imperfect MQW's and Superlattices Interdiffusion in MQW's and SL-Systems Imperfect Superlattices: Period, Thickness, Composition Fluctuations Strained-Layer Superlattices: Tilt, Terracing and Mosaic Spread Scans in the Reciprocal Lattice New Developments Analysis of Quantum Wire Structures Using HRXRD Real Time X-Ray Diffraction Grazing-Incidence X-Ray Techniques 372

7 XIV Contents 6.10 Reflection of X-Rays at Grazing Incidence Specular and Non-Specular Scattering Grazing-Incidence X-Ray Diffraction Summary Concluding Remarks 390 References 392 Subject Index 423