AVS 51st International Symposium
    MEMS and NEMS Monday Sessions
       Session MN-MoP

Paper MN-MoP8
Dissipative Processes in Single-Paddle and Double-Paddle Nanomechanical Silicon Resonators

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: J. Li, University of Pennsylvania
Authors: J. Li, University of Pennsylvania
S. Evoy, University of Pennsylvania
Correspondent: Click to Email
Resonant nanomechanical devices represent powerful platforms for the detection of physical, chemical, and biological processes. However, mechanical quality factor is known to decrease at small dimensions, and the origins of the dominant dissipative mechanisms in resonators of such scales remain misunderstood. We report a study of energy dissipation of nanomechanical resonators through a set of differing devices designed to help isolate and identify dominant dissipative mechanisms. The resonators are fabricated by the nanomachining of silicon-on oxide layers, and characterized by a laser interferometry technique Geometries include double-clamped and single-clamped cantilevers, as well as single-paddle and double-paddle torsional resonators. We will first report on the linear and non-linear dynamics of these devices. Resonant frequencies and the low to mid MHz range and qualities reaching Q = 15 000 are observed in single clamped and doubly clamped structures of width w = 2 um, length from 5 um to 40 um, and thicknesses of t = 150 nm to 400 nm. For the double paddle torsional devices with symmetric geometry, 4 modes of motion are observed which are ascribed to the in-phase/anti-phase flexural, and in-phase/ anti-phase torsional modes of the paddles. For 150 nm thick devices, the resonant frequencies are f0 = 1.9 MHz, 3.55 MHz, 4.10 MHz, and 8.67 MHz respectively. For double paddle design with asymmetric geometry, two flexural modes are observed at 1.19 and 2.86 MHz, respectively. Onset of non-linear behavior is observed under large excitation amplitudes in several of the devices. We will also report a study of the impact of aging, process induced-damage, controlled ion beam induced damage, as well as post-processing annealing on the performance of these resonators. Such results will allow the isolation of the impact of such issues on devices of various designs, dimensions, and geometries.