book

MEMS and Nanotechnology for Gas Sensors

by Sunipa Roy, Chandan Kumar Sarkar

December 2017

Intermediate to advanced

242 pages

6h 47m

English

CRC Press

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1.1 Cleanroom Technology1.2 Microelectromechanical System1.2.1 History1.2.2 Definitions and Classifications1.2.3 Market and Application1.2.4 Materials for MEMS1.3 Significance of MEMSReferences

2.1 Introduction2.2 Silicon: The Base2.2.1 Silicon as a Semiconductor2.2.2 Surface Contamination2.2.2.1 Contaminants on Silicon Wafers2.2.3 Cleaning and Etching2.2.3.1 Cleaning2.2.3.2 Etching2.3 Dielectrics2.3.1 Silicon Dioxide (SiO2)2.3.2 Silicon Nitride (Si3N4)2.3.3 Low-Temperature Oxidation2.3.4 Oxide PropertiesReferences
3.1 Physical Vapour Deposition3.1.1 Vacuum Technology for MEMS3.1.2 e-Beam Evaporation3.1.3 Thermal Evaporation3.1.4 Sputtering3.1.5 Molecular Beam Epitaxy3.2 Chemical Vapour Deposition3.2.1 Atmospheric Pressure CVD (APCVD)3.2.2 Plasma CVD3.2.3 MOCVD3.3 Metallization3.3.1 Different Types of Metallization3.3.2 Methods3.3.2.1 Filament Evaporation3.3.2.2 Electron Beam Evaporation3.3.2.3 Induction Evaporation3.3.2.4 Sputtering3.3.3 Wire BondingReferences
4.1 Introduction4.2 Photoresist for Structuring4.3 Some Important Properties of Photoresist4.3.1 Sensitivity4.3.2 Adhesion4.3.3 Etch Resistance4.3.4 Bubble Formation4.4 Types of Photoresists: Negative and Positive Photoresists4.4.1 Negative Photoresists4.4.2 Positive Photoresists4.5 Designing of Mask Layout4.6 Photolithography Process4.7 Application of Photoresist and Prebake4.8 Alignment, Exposure, and Pattern Formation4.9 PR Developer and Postbake4.10 Stripping (Photoresist Removal)4.11 Some Advanced Lithographic Techniques4.11.1 Electron Beam Lithography4.11.2 Ion Beam Lithography4.11.3 X-Ray Lithography4.11.4 Phase-Shift Lithography
5.1 Introduction5.2 Bulk Micromachining5.2.1 Wet Etching5.2.1.1 Isotropic and Anisotropic: Empirical Observations5.2.1.2 Convex and Concave Corner Compensations5.2.2 Dry Etching5.3 Surface Micromachining5.3.1 Processes5.3.2 Hurdles5.3.3 Lift-Off versus Etch Back5.3.3.1 Lift-Off5.3.3.2 Etch Back5.4 Etch-Stop Technique5.4.1 Boron Etch Stop5.4.2 Electrochemical Etch Stop5.4.3 Photo-Assisted Electrochemical Etch Stop (for n-Type Silicon)5.4.4 Etch Stop at Thin Films: Silicon on Insulator5.5 High-Aspect-Ratio Micromachining5.5.1 LIGA5.5.2 Laser MicromachiningReferences
6.1 Introduction6.2 Need of Microheater6.3 Types of Microheater6.3.1 Closed-Membrane Type6.3.2 Suspended-Membrane Hotplates6.4 Microheater Design Issues6.5 Heater Material Selection6.6 Heater Geometry Selection6.7 Function of Interdigitated Electrode6.8 Software Used6.8.1 Temperature Distribution6.8.2 Mechanical Stability6.8.3 Thermal Response Time6.9 Heating Power Consumption6.10 Fabrication of Microheater6.11 Microheater ArrayReferences
7.1 Introduction7.2 Development of Semiconductor Sensors7.2.1 Fundamentals of Semiconductor Sensors7.2.2 Classification of Semiconductor Sensors7.2.3 Different Structures of Semiconductor Gas Sensors7.2.3.1 Resistive-Type Metal Oxide–Based Gas Sensors7.2.3.2 Schottky-Type Metal Oxide–Based Gas Sensor7.2.3.3 Metal Oxide Homojunction Gas Sensor7.2.3.4 Metal Oxide Heterojunction Gas Sensor7.2.3.5 Mixed Metal Oxide Gas Sensors7.2.3.6 MEMS Gas Sensors7.3 What Is a Nanosensor?7.3.1 Thin Film Sensors7.3.2 Thick-Film Sensors7.3.2.1 Thick-Film Materials7.4 Solid-State Chemical Sensors7.4.1 Metal Oxide Semiconductors7.4.2 Nanocrystalline Metal Oxide Semiconductors7.4.3 Adsorption of Oxygen: Analyses7.4.4 Reaction between Gas (e.g. CH4) and Oxygen7.4.5 Role of Catalyst on Gas Sensing Mechanism7.4.6 Thick- and Thin-Film Fabrication Process7.4.6.1 Bulk Growth7.4.6.2 Substrate Growth7.4.6.3 Chemical Vapour Deposition7.4.6.4 Sputtering7.4.6.5 Chemical Route7.4.7 Sensor Characterizations7.4.7.1 X-Ray Diffraction7.4.7.2 Determination of Crystal Size7.4.7.3 Field Emission Scanning Electron Microscopy7.4.7.4 Transmission Electron Microscopy7.4.7.5 Photoluminescence Spectroscopy7.4.7.6 Fourier Transform Infrared Spectroscopy7.4.7.7 Qualitative Analysis7.4.7.8 UV/VIS Spectroscopy7.4.7.9 Raman Spectroscopy7.4.8 Sensor Reliability IssuesReferences
8.1 Introduction8.2 Properties of Graphene8.2.1 Electronic Property8.2.2 Mechanical Properties8.2.3 Optical Properties8.2.4 Electronic Transport8.2.5 Anomalous Quantum Hall Effect8.2.6 Magnetic Properties8.2.7 Thermal Properties8.3 Characterization Techniques8.3.1 Optical Microscopy8.3.2 Field Emission Scanning Electron Microscopy8.3.3 Atomic Force Microscopy8.3.4 Diffraction Imaging Electron Microscopy8.3.5 Transmission Electron Microscopy8.3.6 Raman Scattering8.4 Synthesis of Single-Layer Graphene/Few-Layer Graphene8.4.1 Micromechanical Exfoliation8.4.2 Chemical Exfoliation8.4.3 Epitaxial Growth on Silicon Carbide (SiC)8.4.4 Chemical Vapour Deposition8.5 Graphene Oxide8.6 Potential Application8.6.1 Graphene Sensors8.7 SummaryReferences
9.1 Introduction9.2 Device Structure: Vertical and Horizontal9.3 Comparison of Vertical and Horizontal Structure9.4 Metal–Insulator–Metal Structure9.5 Nanocrystalline ZnO as Sensing Material9.6 Sensing Layer Deposition by Chemical Route9.6.1 Sol-Gel Method for Synthesis of ZnO Thin Films9.6.2 Chemical Bath Deposition Technique9.6.2.1 Growth Mechanism9.6.3 Chemical Deposition TechniqueReferences
10.1 Introduction10.2 Volatile Organic Compounds10.3 Different Nanostructures10.3.1 Fabrication Processes10.3.2 Characterization Processes10.4 Sensing Mechanism10.5 Measurement Technique10.6 Effect of Relative Humidity on VOC DetectionReferences
11.1 Signal Processing11.2 Smart Sensors11.2.1 System Components11.3 Interface SystemsReferences
12.1 MEMS and Nanotechnology12.2 Automotive Applications: An Elaborated Study12.2.1 Safety12.2.2 Vehicle Diagnostics/Monitoring12.2.3 Engine/Drive Train12.2.4 Comfort, Convenience and Security12.3 Home Appliances12.4 Aerospace12.4.1 Turbulence Control12.5 Environmental Monitoring12.6 Process Engineering12.7 Medical DiagnosticReferences