Understanding Smart Sensors - Nomads.usp

411 Pages·2001·3.04 MB·English

by  Randy Frank

Understanding Smart Sensors
Second Edition
ForalistingofrecenttitlesintheArtechHouseSensorsLibrary,
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Understanding Smart Sensors
Second Edition
Randy Frank
Artech House
Boston (cid:149) London
LibraryofCongressCataloging-in-PublicationData
Frank,Randy.
Understandingsmartsensors/RandyFrank.(cid:151)2nded.
p. cm.(cid:151)(ArtechHousesensorslibrary)
Includesbibliographicalreferencesandindex.
ISBN0-89006-311-7(alk.paper)
1.Detectors(cid:151)Designandconstruction. 2.Programmablecontrollers.
3.Signalprocessing(cid:151)Digitaltechniques. 4.Semiconductors.
5.Applicationspecificintegratedcircuits. I.Title.
TA165.F724 2000
681(cid:146).2(cid:151)dc21 00-021296
CIP
BritishLibraryCataloguinginPublicationData
Frank,Randy
Understandingsmartsensors.(cid:151)2nded.(cid:151)(ArtechHousesensorslibrary)
1.Detectors(cid:151)Designandconstruction 2.Programmablecontrollers
3.Signalprocessing(cid:151)Digitaltechniques 4.Applicationspecificintegratedcircuits
I.Title
681.2
ISBN
1-58053-398-1
CoverandtextdesignbyDarrellJudd
CoverimagecourtesyofSandiaNationalLaboratories
'2000ARTECHHOUSE,INC.
685CantonStreet
Norwood,MA02062
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sioninwritingfromthepublisher.
All terms mentioned in this book that are known to be trademarks or service marks have
beenappropriatelycapitalized.ArtechHousecannotattesttotheaccuracyofthisinformation.
Useofaterminthisbookshouldnotberegardedasaffectingthevalidityofanytrademarkor
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InternationalStandardBookNumber:0-89006-311-7
LibraryofCongressCatalogCardNumber:00-021296
10987654321
This Page Intentionally Left Blank
Dedicatedtothememoryoftheonepersonwhowouldhavelovedtoseethisbook
butdidnot(cid:151)myfather,CarlRobertFrank.
Contents
Preface xix
1 SmartSensorBasics 1
1.1 Introduction 1
1.2 Mechanical-ElectronicTransitionsinSensing 4
1.3 NatureofSensors 5
1.4 IntegrationofMicromachiningand
Microelectronics 11
1.5 Summary 15
References 16
SelectBibliography 16
2 Micromachining 17
2.1 Introduction 17
2.2 BulkMicromachining 19
2.3 WaferBonding 21
2.3.1 Silicon-on-SiliconBonding 22
2.3.2 Silicon-on-Glass(Anodic)Bonding 23
2.3.3 SiliconFusionBonding 24
vii
viii UnderstandingSmartSensors
2.3.4 WaferBondingforMoreComplexStructuresand
AddingICs 25
2.4 SurfaceMicromachining 25
2.4.1 Squeeze-FilmDamping 29
2.4.2 Stiction 29
2.4.3 ParticulateControl 30
2.4.4 CombinationsofSurfaceand
BulkMicromachining 30
2.5 OtherMicromachiningTechniques 31
2.5.1 LIGAProcess 32
2.5.2 Dry-EtchingProcesses 32
2.5.3 Micromilling 36
2.5.4 LasersinMicromachining 36
2.5.5 ChemicalEtchingandICTechnology 37
2.6 OtherMicromachinedMaterials 40
2.6.1 DiamondasanAlternativeSensorMaterial 41
2.6.2 MetalOxidesandPiezoelectricSensing 41
2.6.3 FilmsonMicrostructures 42
2.6.4 MicromachiningMetalStructures 43
2.7 Summary 44
References 44
3 TheNatureofSemiconductorSensorOutput 49
3.1 Introduction 49
3.2 SensorOutputCharacteristics 49
3.2.1 WheatstoneBridge 50
3.2.2 PiezoresistivityinSilicon 52
3.2.3 SemiconductorSensorDefinitions 54
3.2.4 StaticVersusDynamicOperation 57
3.3 OtherSensingTechnologies 57
3.3.1 CapacitiveSensing 58
3.3.2 PiezoelectricSensing 59
Contents ix
3.3.3 HallEffect 60
3.3.4 ChemicalSensors 60
3.3.5 ImprovingSensorCharacteristics 61
3.4 DigitalOutputSensors 62
3.4.1 IncrementalOpticalEncoders 63
3.4.2 DigitalTechniques 64
3.5 Noise/InterferenceAspects 65
3.6 Low-Power,Low-VoltageSensors 66
3.6.1 Impedance 67
3.7 AnalysisofSensitivityImprovement 67
3.7.1 ThinDiaphragm 67
3.7.2 IncreasedDiaphragmArea 67
3.7.3 CombinedSolution:Micromachiningand
Microelectronics 68
3.8 Summary 68
References 69
4 GettingSensorInformationIntotheMCU 71
4.1 Introduction 71
4.2 AmplificationandSignalConditioning 72
4.2.1 InstrumentationAmplifiers 73
4.2.2 SLEEPMODE(cid:153)OperationalAmplifier 75
4.2.3 Rail-to-RailOperationalSimplifiers 76
4.2.4 Switched-CapacitorAmplifier 77
4.2.5 BarometerApplicationCircuit 79
4.2.6 4-to20-mASignalTransmitter 79
4.2.7 SchmittTrigger 79
4.2.8 InherentPower-SupplyRejection 81
4.3 SeparateVersusIntegratedSignalConditioning 82
4.3.1 IntegratedPassiveElements 83
4.3.2 IntegratedActiveElements 84
4.4 DigitalConversion 86