基于垂直扭转梳齿驱动结构的硅微机械扭转微镜的设计加工与表征

为了改善扭转微镜的机电耦合特性和光学特性，提出了一种新的基于SOI硅片的垂直扭转梳齿静电驱动结构．通过有限元与边界元方法，对不同厚度扭转梁的机电耦合特性进行了数值模拟，得到了相应的阈值电压和吸合电压，并提出了几种新的折叠梁结构，以进一步改善器件的机电耦合特性；通过力学分析，从理论上推导了垂直扭转梳齿静电驱动方式微镜的最大扭转角度、阈值电压、扭转刚度以及固有频率，获得了结构参数对器件机电耦合特性的影响机制；最后，利用比例散射理论讨论了表面粗糙度、入射光束波长和入射角度等参数对微镜表面光学反射性能的影响，并利用原子力显微镜测量了微镜的表面粗糙度，理论模拟与实验研究表明，基于SOI硅片和垂直扭转梳齿结构的硅微机械扭转微镜可显著降低器件的驱动电压，提高器件的机电耦合特性和微镜表面的光学反射特性．

Design, Fabrication and Characterization of Novel Micromirror with Vertical Torsion Comb Driver

A new kind of torsion raicromirror with advanced vertical torsion comb driver is proposed and fabricated in silicon on insulator( SOI) wafers by combing with bulk micro machining and surface micro machining technology to improve the electromechanical performances and the optical properties. To evaluate the mechanical robustness and the electrical response , the electromechanical performances of the components are investigated by theory analysis and numerical simulation with finite element method (FEM) method and then the structures are optimized to improve the response speed and reduce the threshold voltage. According to the scalar scattering theory, a mathematical model, which describes the effects of the surface roughness on reflectivity and scattering, is constructed to analyze the optical properties of micromirrors. Then the surface roughness of micromirrors is measured by the atomic force microscope ( AFM). The theoretical and experimental studies manifest that the vertical torsion comb structures with folded beams by SOI wafer are much benefit to decreasing the threshold voltages of actuating the micromirror (making their tilting motion easier) and to enhancing the optical reflectivity of micromirror's surface.