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dc.contributor.authorSamarao, Ashwin Kumaren_US
dc.date.accessioned2011-07-06T16:46:39Z
dc.date.available2011-07-06T16:46:39Z
dc.date.issued2011-04-04en_US
dc.identifier.urihttp://hdl.handle.net/1853/39543
dc.description.abstractThis dissertation reports very novel solutions for the trimming and compensation of various parameters of silicon micromechanical resonators and resonator-arrays. Post-fabrication trimming of resonance frequency to a target value is facilitated by diffusing in a deposited thin metal layer into a Joule-heated silicon resonator. Up to ~400 kHz of trimming-up and trimming-down in a 100 MHz Silicon Bulk Acoustic Resonators (SiBARs) are demonstrated via gold and aluminum diffusion respectively. The dependence of the trimming range on the duration of Joule heating and value of current passed are presented and the possibility of extending the trimming range up to ~4 MHz is demonstrated. Passive temperature compensation techniques are developed to drastically reduce the temperature coefficient of frequency (TCF) of silicon resonators. The dependence of TCF on the charge carriers in silicon are extensively studied and exploited for the very first time to achieve temperature compensation. A charge surplus via degenerate doping using boron and aluminum is shown to reduce a starting TCF of -30 ppm/°C to -1.5 ppm/°C while a charge depletion effected by creating multiple pn-junctions reduces the TCF to -3 ppm/°C. Further, shear acoustic waves in silicon microresonators have also been identified to effect a TCF reduction and have been excited in a concave SiBAR (or CBAR) to exhibit a TCF that is 15 ppm/°C lesser than that of a conventional rectangular SiBAR. The study on quality factor (Q) sensitivity to the various crystallographic axis of transduction in silicon resonators show that the non-repeatability of Q across various fabrication batches are due to the minor angular misalignment of ≤ 0.5° during the photolithography processes. Preferred axes of transduction for minimal misalignment sensitivity are identified and novel low-loss resonator-array type performances are also reported from a single resonator while transduced along certain specific crystallographic axes. Details are presented on an unprecedented new technique to create and fill charge traps on the silicon resonator which allows the operation of the capacitive SiBARs without the application of any polarization voltages (Vp) for the first time, making them very attractive candidates for ultra-low-power oscillator and sensor applications. Finally, a fabrication process that integrates both the capacitive and piezoelectric actuation/sensing schemes in microresonators is developed and is shown to compensate for the parasitics in capacitive silicon resonators while maintaining their high-Q.en_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectAlN-HARPSSen_US
dc.subjectCombined capacitive and piezoelectricen_US
dc.subjectQuality factor sensitivityen_US
dc.subjectTemperature compensationen_US
dc.subjectTCF compensationen_US
dc.subjectElectrical trimmingen_US
dc.subjectTCFen_US
dc.subjectCapacitive silicon microresonatorsen_US
dc.subjectSilicon resonatorsen_US
dc.subjectSilicon microresonatorsen_US
dc.subjectSilicon micromechanical resonatorsen_US
dc.subjectPiezoelectric silicon microresonatorsen_US
dc.subjectSelf polarizeden_US
dc.subjectCharge trapen_US
dc.subjectZero-Vpen_US
dc.subjectHARPSSen_US
dc.subject.lcshMicroelectromechanical systems
dc.subject.lcshResonators
dc.subject.lcshSilicon
dc.titleCompensation and trimming for silicon micromechanical resonators and resonator arrays for timing and spectral processingen_US
dc.typeDissertationen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentElectrical and Computer Engineeringen_US
dc.description.advisorCommittee Chair: Ayazi, Farrokh; Committee Member: Allen, Mark; Committee Member: Brand, Oliver; Committee Member: Garmestani, Hamid; Committee Member: Ghovanloo, Maysamen_US


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