Silicon Nanowires Fabricated By MEMS Technology And Its Properties Characterization

Nano technology has attracted more and more interests in these years because of their potential utilities in next generation integrated circuits and various types of sensors. Up to now, bottom-up and top-down methods have been employed to fabricate silicon nanowires, however, either of them is costly or hard to integrate with current silicon IC process.In this paper, a new method for fabricating silicon nanowires is developed by using MEMS technology. The thickness and width of the nanowires can be accurately controlled to less than 100 nm by employing the multiple oxidation process and the anisotropic etching with a SiO₂ and Si₃N₄ mask separately on a SOI wafer. Aluminum pads are formed on the wires to make low ohmic contact resistance. The suspended nano wires, which are released from the substrate by BHF etching and CO₂ super critical dryer, can avoid a lot of noises from the background.Measurements indicated that the wires perform quite different behavior before and after released. The resistance keeps stable under the protection of SiO₂ shell, while increases with the increasing release time and exposed time in the air, which suggests the surface state of the nanowires plays a key role in the electronic transportation.A Silicon nano resonator was designed in this paper. The resonant frequency was calculated and simulated using FEM. The driving and detecting methods were introduced and the noise and the quality factor of the resonator were discussed.