Ultrafast Stroboscopic Optical Interferometry of Nanoelectromechanical Devices in Damping Pressurized Gas Environment

A broad range of prospective applications of nanoelectromechanical devices necessitates understanding their performance under varying external conditions. We report a comprehensive gas damping study of a series of Si nanobridges and nanocantilevers with thickness of 0.147 $\mu $m, widths ranging from 0.1 to 1 $\mu $m, and lengths from 0.5 to 12 $\mu $m. Free ring-down oscillations of the resonators, capacitively excited by 1 ns 50 V electric pulses, were measured via instantaneous optical interference pictures snapped by a femtosecond laser. The devices response to a range of damping environments was studied, including response to different gases (He, N$_{2}$, CO$_{2}$) in widely ranging pressures from deep vacuum up to 200 bar, all done in a specially designed scanning optical microscopy chamber [1]. The resonator parameters demonstrate three distinct regions of pressure behavior: high vacuum, free molecular flow, and viscous. For each region a qualitative model is presented.\newline [1] O.Svitelskiy et al, Rev.Sci.Instr,\textbf{79} 093701, 2008