Designing positions of grain boundaries in Si thin-film for low-energy-loss optical MEMS/NEMS devices

Polycrystalline Si (poly-Si) thin-film is widely used in optical MEMS/NEMS devices. However, the device performance depends on the crystallized structure in the poly-Si thin-film. We performed metal-induced lateral crystallization (MILC) to design the positions of grain boundaries in the poly-Si thin-film. Thin-film cantilever resonators were fabricated to discuss how grain boundaries affect the oscillation characteristics. Compared with a reference resonator, a resonator in which crystallization was well-designed achieved two-fold increase in Q factor.