Porous Silicon in Practice

Michael J. Sailor has been working in the porous silicon field for 20 years. He received a B.S. degree in Chemistry from Harvey Mudd College (Claremont, CA) and a PhD in Chemistry from Northwestern University (Chicago). He holds the position of Professor in the Department of Chemistry and Biochemistry at the University of California, San Diego (UCSD). His research focuses on the chemistry, electrochemistry, and photophysics of porous silicon, emphasizing applications in medical therapeutics and diagnostics, high-throughput screening, and low power sensing of chemical toxins and pollutants.

Preface

FUNDAMENTALS OF POROUS SILICON PREPARATION
Introduction
Chemical Reactions Governing the Dissolution of Silicon
Experimental Set-up and Terminology for Electrochemical Etching of Porous Silicon
Electrochemical Reactions in the Silicon System
Density, Porosity, and Pore Size Definitions
Mechanisms of Electrochemical Dissolution and Pore Formation
Resume of the Properties of Crystalline Silicon
Choosing, Characterizing, and Preparing a Silicon Wafer

PREPARATION OF MICRO-, MESO-, AND MACRO-POROUS SILICON LAYERS
Etch Cell: Materials and Construction
Power Supply
Other Supplies
Safety Precautions and Handling of Waste
Preparing HF Electrolyte Solutions
Cleaning Wafers Prior to Etching
Preparation of Microporous Silicon from a p-Type Wafer
Preparation of Mesoporous Silicon from a p++-Type Wafer
Preparation of Macroporous, Luminescent Porous Silicon from an n-Type Wafer (Frontside Illumination)
Preparation of Macroporous, Luminescent Porous Silicon from an n-Type Wafer (Back Side Illumination)
Preparation of Porous Silicon by Stain Etching
Preparation of Silicon Nanowire Arrays by Metal-Assisted Etching

PREPARATION OF SPATIALLY MODULATED POROUS SILICON LAYERS
Time-Programmable Current Source
Pore Modulation in the z-Direction: Double Layer
Pore Modulation in the z-Direction: Rugate Filter
More Complicated Photonic Devices: Bragg Stacks, Microcavities, and Multi-Line Spectral Filters
Lateral Pore Gradients (in the x-y Plane)
Patterning in the x-y Plane Using Physical or Virtual Masks
Other Patterning Methods

FREESTANDING POROUS SILICON FILMS AND PARTICLES
Freestanding Films of Porous Silicon-"Lift-offs"
Micron-Scale Particles of Porous Silicon by Ultrasonication of Lift-off Films
Core-Shell (Si/SiO2) Nanoparticles of Luminescent Porous Silicon by Ultrasonication

CHARACTERIZATION OF POROUS SILICON
Gravimetric Determination of Porosity and Thickness
Electron Microscopy and Scanned Probe Imaging Methods
Optical Reflectance Measurements
Porosity, Pore Size, and Pore Size Distribution by Nitrogen Adsorption Analysis (BET, BJH, and BdB Methods)
Measurement of Steady-State Photoluminescence Spectra
Time-Resolved Photoluminescence Spectra
Infrared Spectroscopy of Porous Silicon

CHEMISTRY OF POROUS SILICON
Oxide-Forming Reactions of Porous Silicon
Biological Implications of the Aqueous Chemistry of Porous Silicon
Formation of Silicon-Carbon Bonds
Thermal Carbonization Reactions
Conjugation of Biomolecules to Modified Porous Silicon
Chemical Modification in Tandem with Etching
Metallization Reactions of Porous Silicon

APPENDIX A1. ETCH CELL ENGINEERING DIAGRAMS AND SCHEMATICS
Standard or Small Etch Cell-Complete
Standard Etch Cell Top Piece
Small Etch Cell Top Piece
Etch Cell Base (for Either Standard or Small Etch Cell)
Large Etch Cell-Complete
Large Etch Cell Top Piece
Large Etch Cell Base

APPENDIX A2. SAFETY PRECAUTIONS WHEN WORKING WITH HYDROFLUORIC ACID
Hydrofluoric Acid Hazards
First Aid Measures for HF Contact
Note to Physician
HF Antidote Gel

APPENDIX A3. GAS DOSING CELL ENGINEERING DIAGRAMS AND SCHEMATICS
Gas Dosing Cell Top Piece
Gas Dosing Cell Middle Piece
Gas Dosing Cell Bottom Piece

"The appendices provide engineering drawings for electrochemical etch cells and a gas dosing cell. Appropriate for anyone working in the semiconductor industry, the tutorials are based on a series of summer lectures delivered to a research group." ( Book News , 1 April 2012)