Browsing by Author "Alaca, B. E."

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Open Access
Observation of coupled mechanical resonance modes within suspended 3D nanowire arrays
(Royal Society of Chemistry, 2020) Kılınç, Y.; Karakan, M. Çağatay; Leblebici, Y.; Hanay, Mehmet Selim; Alaca, B. E.
Complex yet compact nanoscale mechanisms have largely been absent due to the rather limited availability of components and integration techniques. Especially missing have been efficient interconnects with adjustable characteristics. To address this issue, we report here, for the first time, the transduction of collective modes in vertically stacked arrays of silicon nanowires suspended between couplers. In addition to the ambitious miniaturization, this composite resonator enables the control of coupling strength through the lithographic definition of coupler stiffness. A direct link is thus established between coupling strength and spectral response for two array architectures with nominally identical resonators but different couplers. A series of unique observations emerged in this platform, such as the splitting of a single mode into two closely spaced modes which raises the possibility of tunable bandpass filters with enhanced spectrum characteristics. Finally, intermodal coupling strengths were measured providing strong evidence about the collective nature of these modes.
Open Access
Piezoresistive silicon nanowire resonators as embedded building blocks in thick SOI
(Institute of Physics Publishing, 2018) Esfahani, M. N.; Kılınç, Y.; Karakan, M. Çağatay; Orhan, Ezgi; Hanay, M. Selim; Leblebici, Y.; Alaca, B. E.
The use of silicon nanowire resonators in nanoelectromechanical systems for new-generation sensing and communication devices faces integration challenges with higher-order structures. Monolithic and deterministic integration of such nanowires with the surrounding microscale architecture within the same thick crystal is a critical aspect for the improvement of throughput, reliability and device functionality. A monolithic and IC-compatible technology based on a tuned combination of etching and protection processes was recently introduced yielding silicon nanowires within a 10 μm-thick device layer. Motivated by its success, the implications of the technology regarding the electromechanical resonance are studied within a particular setting, where the resonator is co-fabricated with all terminals and tuning electrodes. Frequency response is measured via piezoresistive readout with frequency down-mixing. Measurements indicate mechanical resonance with frequencies as high as 100 MHz exhibiting a Lorentzian behavior with proper transition to nonlinearity, while Allan deviation on the order of 3-8 ppm is achieved. Enabling the fabrication of silicon nanowires in thick silicon crystals using conventional semiconductor manufacturing, the present study thus demonstrates an alternative pathway to bottom-up and thin silicon-on-insulator approaches for silicon nanowire resonators.