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dc.contributor.authorYamaner F.Y.en_US
dc.contributor.authorOlcum, S.en_US
dc.contributor.authorBozkurt, A.en_US
dc.contributor.authorKöymen H.en_US
dc.contributor.authorAtalar, Abdullahen_US
dc.date.accessioned2016-02-08T12:16:35Z
dc.date.available2016-02-08T12:16:35Z
dc.date.issued2011en_US
dc.identifier.issn19485719
dc.identifier.urihttp://hdl.handle.net/11693/28291
dc.description.abstractCapacitive micromachined ultrasonic transducers (CMUTs) have a strong potential to compete piezoelectric transducers in high power applications. In a CMUT, obtaining high port pressure competes with high particle velocity: a small gap is required for high electrostatic force while particle displacement is limited by the gap height. On the other hand, it is shown in [1] that CMUT array exhibits radiation impedance maxima over a relatively narrow frequency band. In this paper, we describe a design approach in which CMUT array elements resonate at the frequency of maximum impedance and have gap heights such that the generated electrostatic force in uncollapsed mode, can sustain particle displacement peak amplitude up to the gap height. The CMUT parameters are optimized for around 3 MHz of operation, using both a SPICE model and FEM. The optimized parameters require a thick membrane and low gap heights to get maximum displacement without collapsing membrane during the operation. We used anodic bonding process to fabricate CMUT arrays. A conductive 100 μm silicon wafer is bonded to a glass wafer. Before the bonding process, the silicon wafer is thermally oxidized to create an insulating layer which prevents break down in the operation. Then, the cavities are formed on the insulating layer by a wet etch. The gap height is set to 100 nm. Meanwhile, the glass wafer is dry etched by 120 nm and the etched area is filled by gold evaporation to create the bottom electrodes. The wafers are dipped into piranha solution and bonding process is done afterwards. The fabricated CMUTs are tested in an oil tank. To eliminate the DC voltage which may cause charging problem in the operation, we tried to drive the CMUT array with large continuous wave signals at half of the operating frequency. We observed 1MPa peak to peak pressure with -23 dB second harmonic at the surface of the array (Fig. 1). The proposed design further extends the operation of CMUTs. Observing low harmonic distortions at high output pressure levels, without any charging problem, make CMUT a big candidate for high power applications. © 2011 IEEE.en_US
dc.language.isoEnglishen_US
dc.source.titleIEEE International Ultrasonics Symposium, IUSen_US
dc.relation.isversionofhttp://dx.doi.org/10.1109/ULTSYM.2011.6293596en_US
dc.subjectAnodic bonding processen_US
dc.subjectArray elementsen_US
dc.subjectBonding processen_US
dc.subjectBottom electrodesen_US
dc.subjectBreak downen_US
dc.subjectCapacitive micromachined ultrasonic transduceren_US
dc.subjectContinuous-wave signalsen_US
dc.subjectDC voltageen_US
dc.subjectDesign approachesen_US
dc.subjectGap heighten_US
dc.subjectGlass waferen_US
dc.subjectGold evaporationen_US
dc.subjectHigh outputen_US
dc.subjectHigh power applicationsen_US
dc.subjectInsulating layersen_US
dc.subjectMaximum displacementen_US
dc.subjectNarrow frequency banden_US
dc.subjectOperating frequencyen_US
dc.subjectOptimized parameteren_US
dc.subjectParticle displacementen_US
dc.subjectParticle velocitiesen_US
dc.subjectPeak amplitudeen_US
dc.subjectPeak-to-peaken_US
dc.subjectPiranha solutionsen_US
dc.subjectPressure levelen_US
dc.subjectRadiation impedanceen_US
dc.subjectSecond harmonicsen_US
dc.subjectSmall gapsen_US
dc.subjectSpice modelen_US
dc.subjectThermally oxidizeden_US
dc.subjectThick membranesen_US
dc.subjectWet-etchen_US
dc.subjectDesignen_US
dc.subjectElectrostatic devicesen_US
dc.subjectElectrostatic forceen_US
dc.subjectFrequency bandsen_US
dc.subjectGlassen_US
dc.subjectInsulating materialsen_US
dc.subjectOil tanksen_US
dc.subjectOptimizationen_US
dc.subjectSiliconen_US
dc.subjectSilicon wafersen_US
dc.subjectTransducersen_US
dc.subjectUltrasonic transducersen_US
dc.subjectWet etchingen_US
dc.subjectWafer bondingen_US
dc.titleDesign and implementation of capacitive micromachined ultrasonic transducers for high poweren_US
dc.typeConference Paperen_US
dc.departmentDepartment of Electrical and Electronics Engineering
dc.citation.spage1012en_US
dc.citation.epage1015en_US
dc.identifier.doi10.1109/ULTSYM.2011.6293596en_US


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