Improving Crystallinity of Thin Si Film for Low-Energy-Loss Micro-/Nano-Electromechanical Systems Devices by Metal-Induced Lateral Crystallization Using Biomineralized Ni Nanoparticles

Abstract

The characteristics of thin Si films were investigated in terms of crystallization for low-energy-loss micro-/nano-electromechanical systems (MEMS/NEMS) devices. Metal-induced lateral crystallization (MILC) using Ni nanoparticles accommodated within cage-shaped protein, apoferritin, was applied to an amorphous Si film to obtain a polycrystalline Si (poly-Si) film. The poly-Si film with MILC had crystallized domains of 50–60 µm, whereas the poly-Si film without MILC had grains smaller than 1 µm. Crystallized domains in the poly-Si film with MILC showed almost the same crystalline orientations, whereas those without MILC showed random crystalline orientations. Crystallization-induced tensile stress in the poly-Si film with MILC was increased to 461 MPa (without MILC: 363 MPa). The poly-Si film with MILC was applied to an electrostatically driven MEMS resonator. In the frequency responses, resonant frequency was shifted higher and the Q factor was increased by 20%.