SAW Device/Sensor Modeling for SPICE Simulation …

1 SAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B. BhattacharyyaSAW Device/Sensor Modeling for spices imulation : MOS - AK / GSA INDIA Professor(Email : NoidaAssociation : Suneet Tuli, IIT DelhiAssistance :Indranil Sen, Shishir JainJIIT,NoidaMarch 17, 2012 SAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B. BhattacharyyaPrograms at JIITPASSIVE COMPONENT COMPACT MODELINGP hysical Modeling of Inductor - Inductor as an interconnectSPICE Modeling of MEMS Micromechanical Structures -Cantilevers, MembranesSAW sensor ModelingHigh Temperature MOS ModelingSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B.)

2 BhattacharyyaAgendaSAW BasicsMotivationPrimitive StructuresBenchmark CircuitsBenchmark TestsMotivation For SAW SPICE ModelingMason Equivalent CircuitSPICE ModelingCapacitance ModelingSimulationValidationModel Integration to SPICE Simulator in Verilog-AConclusionReferencesSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B. BhattacharyyaSAW BasicsDepth (wavelengths)13uzuyuy,uzParticle displacementsMonochromatic traveling acoustic wave inz-direction can be described by : particle displacement vector u(z,t), quasistatic electric potential (z,t)zyCompressionDilationSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B.

3 BhattacharyyaSAW BasicsSurface Acoustic Wave(Rayleigh Wave) excitation on thesurface of a piezoelectric substrate through interdigitaltransducer was realized by White[3], at the University ofCalifornia, Berkeley in early 70 s by alternating electric field applied between finger pairs ofIDT periodic strain field in the piezo-substrate to standingacoustic wave Propagating bidirectional wave in elastic wave generated composition of compressionaland shear waves in a fixed mechanical wave velocity3 105cm/sec. Fiveorder smaller than EM Wave Velocity Miniaturization ofelectronic IDT structures are realized by standard microlithographic Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B.

4 BhattacharyyaSAW BasicsThe Wave Energy is confined within wavelengthdistance/depth of the substrate acts as a wave confinement of wave energy makes it extremessensitive to surface perturbation sensor Potential of Wave / Applied voltage to IDT =Transfer Function = = sV1, where s= substratedependent (Freq. Independent) +(z) = s n 1n=0 Vnexp jk(z-zn),zn: position of nth Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B. BhattacharyyaMotivationSurface Acoustic Waves are sensitive toAmbient TemperatureForcesAccelerationElectric Field StrengthDew PointGas concentrationGas FlowPathogens,E-coli, virus, bacteria, DNAGas trace in environment(e-nose)Automobile emissionA wide range of sensorsIn Communication:Delay Line, Band pass filters, Dispersive filters, Resonators,Convolvers, Correlators, RF Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B.

5 BhattacharyyaPrimitive IDT Structures - IFingerWidthFingerSpacingPeriod(p)p/2 ApertureVoltage sourceSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B. BhattacharyyaPrimitive IDT Structure - II Delay LinePiezoelectricSubstrate +A +BI2V1I2V1 TransmitterReceiverSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B. BhattacharyyaDouble-Electrode IDT Structure = Cancellation ofReflection from Metal ElectrodesPiezoelectricSubstrateI2V1I2V1 0 8 8 TransmitterReceiver zz0=RP K22+Rm h +(h )2[Forh << ] K22 Mechanical loadingEnergy storageSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B.

6 BhattacharyyaMonolithic SAW Structure : SAW -on -Silicon(S O S)[12]Dielectrics(overglass +intermetal + gate oxide )IDT s(Metal 1)N-Well HeatersSi SubstratePolyMetal 1 Metal 2 Absorberunexposed oxideDelay line(Si exposed)RF Magnetron Sputtered ZnOZnO/Si in CMOS TechnologyS/i(Smart/Intelligent) SAWSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B. BhattacharyyaRelationship between Transducer Periodicity andCoherently Excited Waves+ x+-+-+n=1n=3dSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B.

7 BhattacharyyaInput / Output Equivalent for a SAW Delay LineVinRsCtGa(f)ICtGa(f)RLINPUT IDTOUTPUT IDTabSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B. BhattacharyyaMason Crossed-Field Model[13] CS2CS21 : 11 : 1 CSCEQCSCEQTANEQTANEQTANEQTANEQn2n1 LRn3n4n5n6n8 TANEQ=jZ0tan 2,CSCEQ= jZ0csc , = ff0,Z0=1k2 Csf0,f0= 0Lk : electromechanical coupling constant ;Cs: electrode capacitance per section 0= SAW velocity for free region ; L : the length of one periodCdDiscontinuityCapacitance[15]SAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B.

8 BhattacharyyaMason Modified Crossed-Field Model[13] n1n2n7n8n9n10n11n12n13n14n15n16n17n18n19 n20n22n23n24CS2CS2 CSC0 CSCMCSC0 CSC0 CSCMCSC0 TANOTANOTANMTANMTANOTANOTANOTANOTANMTANM TANOTANOLRTAN0 =jZ0tan 02,CSC0 = jZ0csc 0,TANM=jZmtan m2,CSCM= jZmcsc m, 0= 4ff0, m= 2ffm,Z0=1k2 Csf0,Zm=1k2 Csfm,f0= 0L,fm= mLk : electromechanical coupling constant ;Cs: electrode capacitance per section 0= SAW velocity for free region ; m: SAW velocity for metallized region ; L : the length of one periodSAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B.

9 BhattacharyyaFoster s Equivalent Network Steps to SPICE elements represent lossless transmission lines. Thetransformer figures due to electromechanical coupling of thepiezoelectric entire transducer is consisting of N periodic section is incascade acoustically and is parallel s crossed-field model is believed to produce closeragreement with experimental Modeling part can be resolved into following Modeling (Transmitter and Receiver).2 Delay path between Transmitter and Receiver electronics Modeling (matching network, layoutparasitics, bonding/packaging and pcb integration, signalprocessing circuits etc.)

10 SAW Device/Sensor Modeling for SPICE Simulation : MOS - AK / GSA INDIA 2012c B. BhattacharyyaFoster s Equivalent NetworkIn Mason s model, TANEQ, CSCEQ, TAN0, TANM, CSC0,CSCM are frequency model replaces above terms by LC network obtainedusing Foster s method yielding a network corresponding to thegiven functional s method states that an input impedance function canbe completed specified by a networkthrough its poles and zero locations andits value at some non-zero / non-pole compact Modeling to ensure computational stability asmall quantity( >0)