In-Plane Air Damping of NEMS and MEMS Resonators

This paper presents a study of the quality factor dependence on the geometrical parameters of in-plane clamped-clamped micro- and nano-beams capacitive structures at low-to-high pressure range. We found that smaller length and larger beam thickness maximize the quality factor. To minimize squeeze film damping, the structures have been fabricated with large capacitive air gaps. Despite the high ratio of the gap/thickness, we report significant effect of the gap width on the quality factor. It is found that, for micro-beams, this effect is limited at low pressure while for nano-beams, it continues until high pressure range. The geometry and the air gap effects on the damping of beams resonators have been examined experimentally. A finite-element study of the effect of the capacitive gap for in-plane resonators of one and two-side electrodes is presented. It is found that the presence of the double electrodes for in-plane resonators can cause significant drop of the quality factor compared to the single-sided beam resonator.