Electrostatically Actuated Nano Tweezers Fabricated on Micro Processed Electrodes

Abstract

Nanoscale tweezers are integrated to deep reactive ion etching (DRIE)-processed microelectrodes by localized chemical vapor deposition using focused ion beam (FIB-CVD). The MEMS electrodes for electrostatic actuation of nano tweezers are fabricated on a heavily doped SOI wafer, which works as the interconnecting platform to control nanoscale device from macro-world. Unlike the carbon nano tube (CNT)-based nano tweezers, the dimension and gap between the pillars are well-controlled such that the designed range of motion and the operation voltage are easily achieved. Compared to repulsive nano tweezers, the actuation voltage is at least an order lower for the similar range of motion. Repeated electrostatic tweezing action for two sets of tweezers shapes has been successfully demonstrated. For bent type tweezers, short pillar is deposited on the edge of electrode to adjust the initial gap of tweezers which measures 17 mum in length and 300 nm in diameter. The threshold voltages that causes snap-down are dependent on the initial gap size of the unactuated pillars, and the measured value are 93 V for 3.5 mum and 30 V for 2.21 mum gaps. The dimension of straight type tweezers is 19.6 mum in length and 300 nm in diameter with 6.9 mum initial gap distance. Tweezing range is 3.4 mum and snap down voltage is 102 V. Young's modulus of the FIB-CVD carbon tweezers is estimated to be 377 GPa based on the experimental results. Tweezers with complicated 3-dimensional shapes are also presented