Acoustic wave sensors : theory, design, and physico-chemical applications

445 Pages·1997·6.313 MB·English

by  David Stephen Ballantine, et al

Acoustic Wave Sensors
,yroehT Design, and lacimehC-ocisyhP
snoitacilppA
D. S. Ballantine, Jr. R. M. White
Chemistry Department Department of Electrical Engineering
Northern Illinois University and Computer Science
De Kalb, Illinois Berkeley Sensor & Actuator Center
University of California
Berkeley, California
S. J. Martin
A. J. Ricco
G. C. Frye E. T. Zellers
Microsensor R&D Department of Environmental
Sandia National Laboratories and Industrial Health
Albuquerque, New Mexico Department of Chemistry
University of Michigan
Ann Arbor, Michigan
H. Wohltjen
Microsensor Systems, Inc.
Bowling Green, Kentucky
ACADEMIC PRESS
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Acknowledgments
We thank Barb Wampler and Kathy Rice of Sandia National
Laboratories for assistance with graphics and proof reading of
many sections of this book, and Stuart Wenzel and Ben Costello
of Berkeley Microlnstruments for providing many of the illus-
trations in Chapter 3.
This book is printed on acid free paper. (~
Copyright © 1997 by Academic Press
All fights reserved.
No part of this publication may be reproduced or transmitted in
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Library of Congress Cataloging-in-Publication Data
Acoustic wave sensors : theory, design, and physico-chemical
applications / D.S. Ballantine, rJ .... et al..
p. cm.----(Applications of modern acoustics)
Includes bibliographical references and index.
ISBN 0-12-077460-7 (alk. paper)
.1 Acoustic surface wave devices. 2. Detectors. 3. Chemical de-
tectors. 4. Biosensors. I. Ballantine, David Stephen. II. Series.
TK5984.A38 1996 96-21931
681 '.2---dc20 CIP
Printed in the United States of America
96 97 98 99 00 MV 9 8 7 6 5 4 3 2 1
Series Preface
Modern Applications of Acoustics is a series, that will, in the hopes of the edi-
tors, present the most exciting developments in the applications of acoustics that
have emerged in the past few decades. This first seven-author volume, which
was already nearing publication when the series was conceived, is an auspicious
beginning. It can be argued that all living entities have their own built-in bio-
logical acoustic sensors, be they aural or tactile, whose sensitivity, in some in-
stances, is at the optimum signal-to-noise level. For instance, it is known that if
the human ear were any more sensitive, Brownian noise would mask the intelli-
gibility of perceived sound. It is possible that the sound emitted by crackling dry
leaves and twigs may be the first artificial sensors devised by humans for de-
tecting game or intruders. The sensors described in this volume avail themselves
of the most modern microphotolithographic techniques, and use sophisticated sig-
nal processing techniques that could not be achieved without the use of the for-
midable power of modern computers. But, the germinal ideas are the product of
human ingenuity.
The editors envision that future volumes will be authored by scientists and
engineers who are internationally recognized in their fields as experts and who
have made major contributions to the advancement of their areas. The series will
include volumes that may be prepared by a single author, a few co-authors, or
in the instance of emerging fields, the required expertise may best be harnessed
by a guest editor who then will solicit contributions from many experts in nar-
rower subfields.
At present the editors are actively pursuing the publication of volumes in ther-
xi
xii Series Preface
moacoustic engines, resonant ultrasonic spectroscopy, modem architectural
design, active noise suppression, biological and industrial flow detection,
nondestructive evaluation, underwater detection, acoustic tissue characterization,
sonoluminescense, and more.
The editors dedicate this series to their thesis advisor and mentor, Professor
Isadore Rudnick.
Richard Stern
Moises Levy
Table of Contents
Series Preface xi
Chapter 1 Why Acoustic Sensors?
1.1 What Is a Sensor?
2.1 The Microsensor Revolution and the Role of Acoustics
3.1 Where They Fit and How They Are Used
1.4 About the Authors and the Rest of the Book
References
Chapter 2 Fundamentals of Acoustic Waves 10
2.1 Wave Propagation in an Elastic Medium 01
2.1.1 Displacement, Stress, dna Strain 21
2.1.2 Equation of noitoM 51
2.1.3 Reduced Notation (Engineering )noitatoN 61
2.1.4 ehT Wave noitauqE 81
2.1.5 Bulk-wave gnipmaD 12
2.2 Piezoelectricity 22
2.2.1 ehT Wave Equation for cirtceleozeiP slairetaM 52
2.2.2 Energy Density and Power Flow 82
2.3 Perturbations in Acoustic Wave Propagation 13
References 35
vi Contents
Chapter 3 Acoustic Wave Sensors and Responses 36
3.1 Thickness-Shear Mode (TSM) Resonator 38
3.1.1 TSM Resonator Mass Sensitivity 43
3.1.2 Electrical Characteristics of an Unperturbed TSM Resonato 54
3.1.3 Electrical Characteristics of the TSM Resonator with an Arbitrary Surface
Perturbation 48
3.1.4 Electrical Characteristics of TSM Resonator with an
Ideal Mass Layer 25
3.1.5 Electrical Characteristics of the TSM Resonator Contacted by Liquid 54
3.1.6 Effect of Surface Roughness on TSM Resonator Liquid Loading 95
3.1.7 Solid/Liquid Boundary Conditions and Wetting of Textured Surfaces 62
3.1.8 Dynamics of a TSM Resonator with a Viscoelastic Film 66
3.1.9 Electrical Characteristics of a TSM Resonator Coated with a Viscoelastic Film 68
3.2 Surface Acoustic Wave (SAW) Devices 70
3.2.1 SAW Excitation and Detection 27
3.2.2 lnterdigital Transducer Frequency Response 74
3.2.3 SAW Perturbation Mechanisms 87
3.2.4 SAW Mass Loading 80
3.2.5 SAW Acoustoelectric Response 38
3.2.6 Parametric Representation of the SAW Acoustoelectric Response 98
3.2.7 Elastic and Viscoelastic Films on a SAW Device 98
3.2.8 SAW Response from Acoustically Thin Films 39
3.2.9 SAW Response from Acoustically Thick Films 96
3.3 Acoustic Plate Mode (APM) Devices 99
3.3.1 APM/Liquid Interactions 301
3.3.2 Mass Sensitivity of the APM 401
3.3.3 APM Liquid Loading 601
3.3.4 APM Acoustoelectric Coupling 901
3.4 Flexural Plate-Wave (FPW) Devices 111
3.4.1 Flexural Plate Waves 311
1.1.4.3 roivaheB of eht WPF seiticoleV dna elcitraP snoitoM
3.4.2 FPW Perturbation Mechanisms i 91
1.2.4.3 stceffE of gnisaercnI eht aerA/ssaM of eht Plate 2.2.4.3 stceffE of gnidaoL
htiw a suocsiV-noN Fluid 3.2.4.3 ciftemivarG noitceteD of na deddA ssaM ni a diuqiL
4.2.4.3 stceffE of gnidaoL htiw a suocsiV Liquid 5.2.4.3 rehtO snoitabrutreP
3.4.3 FPW Kinetic Effects: Pumping and Mixing 431
1.3.4.3 latnemirepxE snoitavresbO 2.3.4.3 anemonehP Involved 3.3.4.3 snoitacilppA
3.5 Comparison of Acoustic Sensing Devices 140
3.5.1 Recently Introduced Acoustic Sensors 041
Contents vii
1.1.5.3 Thin-Film lanoisserpmoC evaW-kluB Sensor 3.5.1.2 Surface Transverse evaW
)WTS( Sensor 3.5.1.3 Love Wave Sensor 3.5, I A Thin-Rod evaW-laruxelF rosneS
3.5.2 Comparison of Gravimetric Acoustic Sensors 141
3.5.3 Qualitative Comparison of Acoustic Sensors 145
References 145
Chapter 4: Materials Characterization 150
4.1 Overview of Applications 151
4.1.1 Characterization of Thin Film Materials 151
4.1.2 Characterization of Fluid Properties 153
4.2 Characterization of Polymers 154
4.2.1 Viscoelastic Properties 551
.2.4 I. 1 noitanimreteD of noitisnarT Temperatures 4.2.1.2 noitcartxE of egarotS
dna Loss Moduli 4.2.1.3 noitprosbA anemonehP dna noitazicitsalP
4.2.2 Diffusion and Permeation 761
1.2.2.4 emiT-laeR Monitoring 4.2.2.2 naikciF Diffusion 4.2.2.3 naikciF-noN noisuffiD
4.2.2.4 noitaemreP Rate noitaulavE
4.3 Surface Adsorption and Characterization of Porous Films 179
4.3.1 Physisorption: Characterizing Surfaces and Pores 179
1.1.3.4 gniziretcarahC secafruS dna Adsorbed Layers 4.3.1.2 gniziretcarahC Film
ecafruS Area dna Pore Size Distribution 4.3.1.3 WA Device stluseR with suoroP Films
4.3.2 Chemisorption 191
1.2.3.4 weivrevO of Chemisorption 4.3.2.2 gnilbmessA-fleS Films
4.3.3 Adsorption at Solid-Liquid Interfaces 391
4.4 Real-Time Monitoring of Chemical and Materials Processes 197
4.4.1 Monitoring Film and Particle Deposition and Removal 791
4.4.2 Polymerization Reactions 200
4.4.3 Corrosion Monitoring 205
4.4.4 Electrochemical Studies 207
4.4.5 Miscellaneous Materials/Process Characterization 209
4.5 Summary 210
References 212
Chapter 5: Chemical and Biological Sensors 222
5.1 Introduction 222
5.2 Detection Mechanisms 223
5.2.1 Mass Loading 225
viii Contents
5.2.2 Mechanical Properties 228
5.2.3 Rheoiogical Properties 332
5.2.4 Electrical Properties 234
5.2.5 Thermal Effects 832
5.3 Performance Criteria 238
5.3.1 Selectivity 239
5.3.2 Reversibility: Sensors and Dosimeters 142
5.3.3 Sensitivity 342
5.3.4 Dynamic Range 244
5.3.5 Stability, Repeatability, Reliability, and Reproducibility 542
5.3.6 Response Time 246
7.3.5 Environmental Effects 247
5.4 Coating-Analyte Interactions and Acoustic-Wave Chemical Sensors 248
5.4.1 Physical and Chemical Interactions 152
5.4.2 Thermodynamics of Adsorption: Adsorption Isotherms 256
1.2.4.5 riumgnaL mrehtosI 2.2.4.5 hcildnoerF noitprosdA mrehtosI
3.2.4.5 TEB noitprosdA Model 4.2.4.5 yrallipaC ;noitasnednoC Other sledoM
5.4.3 Kinetics of Adsorption 266
1.3.4.5 Rate snoisserpxE 2.3.4.5 tropsnarT hguorht smliF
5.4.4 Adsorption-Based Acoustic-Wave Sensors 272
1.4.4.5 nommoC slairetaM rof lacisyhP noitprosdA 2.4.4.5 desaB-noitprosisyhP srosneS
3.4.4.5 dosaB-noitprosimehC srosneS
5.4.5 Absorption and Polymer Sorption 288
1.5.4.5 weivrevO of remyloP noitproS smrehtosI 2.5.4.5 lamroN gnilioB tnioP ledoM
3.5.4.5 ralugeR noituloS yroehT dnarbedliH( ytilibuloS )retemaraP 4.5.4.5 raeniL -avloS
noit ygrenE spihsnoitaleR citamorhcotavloS( )sretemaraP 5,5.4.5 laciripmE sdohteM
5.4.6 Absorption-Based Sensors 300
5.4.7 Biochemical Interactions and Acoustic-Wave Sensors 306
5.5 Selectivity Revisited: Sensor Arrays and Pattern Recognition 313
5.5.1 Coating Selection 314
5.5.2 Sensor Array Data Interpretation 513
5.6 Summary 320
References 320
Chapter 6: Practical Aspects of Acoustic-Wave Sensors 331
6.1 Introduction 331
6.2 Basics of Acoustic-Wave Sensor Design and Fabrication 332
6.2.1 Device Configurations 332
stnetnoC xi
1.1.2.6 :troP-enO kluB dna WAS srotanoseR 2.1.2.6 :stroP-owT ,WAS MPA
dna WPF yaleD seniL dna srotanoseR
6.2.2 Substrate Materials 733
6.2.3 Interdigital Transducer Design 339
6.2.4 Microfabrication Technology 243
1.4.2.6 lateM noitceleS dna noitisopeD 2.4.2.6 cihpargohtilotohP gninrettaP
3.4.2.6 noitaraperP rof gnigakcaP
6.2.5 Chemically Selective Coatings: Requirements and Methods of Application 743
.5.2.6 I lareneG gnitaoC stnemeriuqeR 2.5.2.6 esahP-noituloS sdohteM of noitacilppA
3.5.2.6 esahP-ropaV sdohteM of noitacilppA
3.6 Acoustic-Wave Measurement Technology 553
6.3.1 Instrumentation and Components 553
6.3.2 Measurement of Acoustic-Wave Device Frequency Response 753
1.2.3.6 troP-enO Devices 2.2.3.6 troP-owT seciveD
6.3.3 Real-Time Monitoring of Acoustic-Wave Devices for Sensing
and Characterization Applications 163
.3.3.6 I suoenatlumiS tnemerusaeM of evaW-citsuocA yticoleV dna noitaunettA
2.3.3.6 troP-enO Devices 3.3.3.6 troP-owT :seciveD rotallicsO Circuits 4.3.3.6 -owT
troF :seciveD noitagaporP stnemerusaeM 5.3.3.6 troP-owT :seciveD dekcoL-esahP spooL
6.4 Controlling the Sensor Environment 573
6.4.1 Temperature Effects and the Need for Temperature Control 573
6.4.2 Pressure Effects 873
6,4.3 Flow-Rate Effects 873
6.4.4 Sensor Packaging Considerations 973
6.4.5 Remote Sensor Location Schemes 283
6.5 Enhancing Sensor Performance by System Design 384
6.5.1 Baseline Drift Compensation Strategies 483
6.5.2 Vapor Concentration Enrichment 386
6.5.3 Array Sensors and Pattern Recognition 390
6.6 System Design Challenges 393
References 394
Appendix :A Lists of Symbols yb retpahC 396
Appendix :B Glossary of smreT 408
Appendix :C Polymeric slairetaM 421
Appendix :D Commercial Sources for Acoustic-Wave ,setartsbuS
Devices,and Systems 428
Index 430
retpahC 1 yhW ?srosneS
Acoustic
Precise measurement tools are necessary parts of most successful scientific and
engineering enterprises. The sensing devices that we consider in this volume are
such tools, capable of measuring physical, chemical, and biological quantities.
What they have in common is that they all employ acoustic waves in their op-
eration. The purpose of this introductory chapter is to provide an overview of
these devices, and to answer the question: why use acoustic sensors?
1.1 What Is a Sensor?
The sensors we consider here produce an output signal in response to some in-
put quantity, as indicated schematically in Figure 1.1(top). The output signal is
usually electrical- an analog voltage or current, a stream of digital voltage
pulses, or possibly an oscillatory voltage whose frequency represents the value
of the input quantity. The range of input quantities covered in this book is large,
including physical quantities such as the mechanical properties of thin films, and
chemical and biological quantities such as the concentrations and identities of
unknown species in air or liquid media.
Inside the typical sensor of Figure l.l(top), a process of transduction takes
place, converting the input event into an electrical signal. The sensor may also
contain circuitry that converts the often feeble electrical signal from the trans-
duction process into a more robust form suitable for use outside the sensor itself.
The output signal may be stored in a computer memory for later examination.
Possible applications would have the signal activating an alarm to warn of the
1
ACOUSTIC WAVE SENSORS Copyright O 199"/by Academic sserP
All tights of reproduction in any form .devreser
ISBN 7-064770-21-0