Farrokh Ayazi

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This paper presents an analytical model for support loss in clamped–free (C–F) and clamped–clamped (C–C) micromachined beam resonators with in-plane flexural vibrations. In this model, the flexural vibration of a beam resonator is described using the beam theory. An elastic wave excited by the shear stress of the beam resonator and propagating in the(More)
This paper presents the design, fabrication, and testing of an 80m-thick, 1.1 mm in diameter high aspect-ratio (20:1) polysilicon ring gyroscope (PRG). The vibrating ring gyroscope was fabricated through the high aspect-ratio combined poly and single-crystal silicon MEMS technology (HARPSS). This all-silicon single-wafer technology is capable of producing(More)
We discuss the contribution of phonon interactions in determining the upper limit of f.Q product in micromechanical resonators. There is a perception in the MEMS community that the maximum f.Q product of a microresonator is limited to a “frequency-independent constant” determined by the material properties of the resonator [1]. In this paper, we discuss(More)
This paper studies the application of lateral bulk acoustic thin-film piezoelectric-on-substrate (TPoS) resonators in high-frequency reference oscillators. Low-motional-impedance TPoS resonators are designed and fabricated in 2 classes--high-order and coupled-array. Devices of each class are used to assemble reference oscillators and the performance(More)
This paper reports on a new class of high-Q single-crystal silicon (SCS) resonators that are piezoelectrically actuated and sensed, and have voltage-tunable center frequencies. The resonating element is made out of the SCS device layer of a SOI wafer. In a unique manner, piezoelectric transduction was integrated with capacitive fine-tuning of the resonator(More)
The paper reports on the implementation and characterization of thick bulk mode VHF capacitive disk resonators with reduced motional resistance. Single crystal silicon (SCS) side-supported disk resonators with thickness of 18 /spl mu/m and 10 /spl mu/m and capacitive gaps of 160 nm and 75 nm, respectively (gap aspect-ratio>130), are fabricated on(More)
This paper presents a single-wafer high aspect-ratio micromachining technology capable of simultaneously producing tens to hundreds of micrometers thick electrically isolated poly and single-crystal silicon microstructures. High aspect-ratio polysilicon structures are created by refilling hundreds of micrometers deep trenches with polysilicon deposited over(More)
This paper reports on the design, implementation and characterization of high-frequency single crystal silicon (SCS) block resonators with piezoelectric electromechanical transducers. The resonators are fabricated on 4μm thick SOI substrates and use sputtered ZnO as the piezo material. The centrally-supported blocks can operate in their first and higher(More)
This paper reports on the fabrication and characterization of single-crystal silicon (SCS) capacitive resonators with operating frequencies in the HF (3-30MHz) and VHF (30-300MHz) range. In-plane ultra-stiff SCS resonators with polysilicon electrodes and self-aligned 90nm vertical capacitive gaps have been fabricated on SOI substrates using a HARPSS-like(More)