Improving the quality factor of polycrystalline Si thin-film micromechanical resonators by metal-induced lateral crystallization using biomineralized Ni nanoparticles

Abstract

We employed metal-induced lateral crystallization (MILC), using Ni nanoparticles synthesized within cage-shaped protein molecules, to crystallize an amorphous Si film into a polycrystalline film. This process allowed us to choose the crystallization sites of the polycrystalline silicon (poly-Si) film and enlarged the average grain size. We fabricated cantilever resonators from the poly-Si film to characterize them and extract quality factors. The reference resonator, fabricated without MILC, had a quality factor of 12 100, while the resonator crystallized along the axial direction had a quality factor of 26 200. Two-fold increase was achieved by tuning the crystal structure of the poly-Si film.