应用于激光雷达的二维静电微镜设计

Study on 2D electrostatic-driven micro scanning mirror applied to LiDAR

设计了一种应用于激光雷达的二维静电驱动谐振式微机电系统(MEMS)扫描微镜。基于MEMS技术对微镜加工工艺进行设计,简化了电隔离槽制备工艺,利用在绝缘体上硅(SOI)晶圆顶层硅刻蚀微镜结构的同时刻蚀电隔离槽,无需填充绝缘材料,实现动静梳齿的电绝缘;利用SOI晶圆底层硅的背面刻蚀结构,实现机械结构的连接,保证二维微镜结构的完整性。制备出镜面直径为4 mm二维谐振扫描微镜,并运用有限元法模拟微镜谐振频率,其仿真结果与实际测得的结果基本一致。在40,50 V的方波电压驱动下,快轴和慢轴的测量谐振频率分别为1618.2,328.2 Hz,相对应的光学扫描角度分别为16°,21°,并得到在此谐振工作下的李萨如扫描图。

A two-dimensional electrostatic-driven micro scanning mirror for the Li DAR application is designed.Based on the micro-electro-mechanical system( MEMS) technology,the micromirror processing process is designed to simplify the preparation process of the electrical isolation trench. The micromirror structures and isolation trenches between combs are patterned and etched at the same steps on the top silicon layer of a silicon on insulator( SOI) wafer. These trenches are not filled with insulating materials. During backside releasing etch on the bottom silicon layer of the SOI wafer,mechanical structures are designed and formed to maintain the integrity of the micromirror. A two-dimensional resonant micromirror with Φ4 mm mirror surface is prepared,resonant frequency of micromirror is analyzed by using finite element simulation, the simulation results are consistent with the measurement data of the device. The measured resonant frequencies of the two-dimensional micromirror for the fast and slow-axis are 1618. 2 Hz and 328. 2 Hz,respectively. The corresponding optical scanning angles are 16° and21° respectively. with the square wave voltages of 40 V and 50 V. In addition,the dual axis of the micromirror works at this frequency and successfully scans the Lissajous figure.