High-Yield Fabrication and Characterizations of Sub-50 nm Nanomechanical Resonators
C. Guthy, R. Das, S. Evoy
University of Alberta, CA
Keywords: mechanical resonance, silicon carbonitride, NEMS, interferometric detection, quality factor, energy dissipation, surface loss effects
Abstract:We report the machining and resonant analysis of SiCN doubly-clamped nanomechanical resonators as narrow as 35 nm with a yield approaching 100%. These are the narrowest suspended structures ever produced by a surface machining technique. The nanoresonators were actuated using a piezoelectric disk, and their resonant response analyzed using optical interferometry. Resonators with widths ranging from 35 nm to 150 nm and length from 10 to 24 um were analyzed at room temperature and in the 10-100 mTorr pressure range. Resonant frequencies in the 4-15 MHz range and quality factors in the 1000 - 7000 range were observed. The quality factor exhibits a decreasing trend with decreasing resonator width and is independent of the resonator length or resonant frequency. Based on our analysis we conclude that surface loss effects dominate the overall dissipative processes. Additionally, the performance of 35 nm, 100 nm and 350 nm wide devices was investigated as a function of vacuum level in the 0.0001-10 Torr range. Although the resonance quality is lower for narrower resonantors, they can be operated at poorer vacuum levels without a negative effect on their performance.