Scaling Effect Induced Rapid Quenching Improves the Performance of Microfabricated Electrostatic Micromirrors

In this paper we study the scaling effect on the heat transfer of microfabricated electrostatic micromirrors with polysilicon and gold bimorph structure. Based on scaling effect study, it is found that as the characteristic length of micromirror reduces, rapid cooling occurs, and we implemented the scaling effect to perform thermal processing to cause rapid quenching and plastic deformation on microfabricated micromirrors to improve its performance, including the maximum out-of-plane displacement and bandwidth. Electrostatic micromirrors were fabricated by a two-layer polysilicon microfabrication process. Measurement results demonstrated that after the thermal processing, the maximum out-of-plane displacement increased by 60.8%, from 1.25 μm to 2.01 μm, and the 3dB bandwidth was increased by 40.7%, from 1.35 kHz to 1.90 kHz.