Linear and nonlinear dynamics of silicon nanoresonators
Abstract
Resonant nanoelectromechanical systems (NEMS) have the potential to significantly impact mass sensing, signal processing and field detection applications, if the challenges associated with processing, material and geometric variability can be mitigated. The research presented here details some breakthroughs in the design and development of resonant NEMS aimed at addressing these challenges. Specifically, this work investigates the dynamic response of two different implementations of a two-degree-of-freedom nanomechanical resonator driven by electrostatic and thermal noise excitations. The first part of this work investigates the impact of asymmetric cross-sectional geometry on the near-resonant response of electrostatically and thermally actuated silicon nanowires. The work demonstrates that dimensional variances of less than 2% qualitatively alter the near-resonant response of these nanosystems, rendering a non-Lorentzian frequency response structure. Theoretical and experimental results demonstrate that this effect is independent of material properties and device boundary conditions and can be easily modeled using a two-degree-of-freedom system. Proper understanding of the aforementioned asymmetry is believed to be essential in the characterization of the dynamic response of resonant nanotube and nanowire systems, and thus the predictive design and development of such devices. The second part of this work details the fabrication, experimental characterization, and tuning of electrostatically actuated, dual-gate, silicon nanoelectromechanical resonators. Though the dynamics of these highly nonlinear systems are inherently of interest, they are of practical interest due to the fact they can be fabricated on a silicon on insulator (SOI) substrate using only top-down microfabrication techniques and can be easily integrated with SOI-CMOS transistors. As such, these resonators enable the development of fully integrated CMOS-NEMS with highly-tunable nonlinear frequency response characteristics.
Degree
M.S.M.E.
Advisors
Rhoads, Purdue University.
Subject Area
Mechanical engineering|Nanotechnology
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