光子学报, 2013, 42 (5): 515, 网络出版: 2013-05-22
飞秒激光多光束干涉光刻硅表面减反微结构
Femtosecond Laser Multibeam Interference Lithography Antireflective Microstructure on Silicon Surface
飞秒激光 空间光调制器 多光束干涉 单晶硅 减反微结构 Femtosecond laser Spatial light modulator Multibeam interference Single crystal silicon Antireflective microstructure
摘要
为了得到均匀分布的硅表面微结构,提出了一种利用多束激光干涉光刻的方法来实现对硅表面微结构分布特征的控制.利用空间光调制器实现飞秒激光多光束干涉,形成分布均匀、周期可控的空间点阵,利用聚焦的空间点阵在单晶硅表面烧蚀得到规则分布的凹坑状结构,并通过改变附加给空间光调制器的相位实现对微结构分布特征及间距的控制.用扫描电子显微镜和分光光度计分别对结构的形貌特征和光学特性进行了测量,结果表明:采用底角为2°的四棱锥镜相位形成四光束干涉,通过10×物镜聚焦,在激光功率25 mW、曝光时间30 s时,可以形成间距约为3.3 μm的密排凹坑微结构,所形成的凹坑结构具有良好的减反效果,在1.2~2 μm近红外波段的透过率相对抛光硅平均提高了11.5%.
Abstract
In order to obtain uniform distribution silicon surface microstructure, a new method was proposed based on multibeam interference lithography to relaise the controlling of the distribution character of the microstructure. Femtosecond laser multibeam interference was formed by Spatial Light Modulator (SLM), and the uniform distribution multispots with the controllable period were generated. By using these multispots, the regular distribution concave structures were fabricated on silicon surface, and the distribution character and period was flexiblly controlled by shift the phase masks on SLM. The morphology and optical character of the microstructure were measured with Scanning Electron Microscopy (SEM) and spectrophotometer. Experimental results show that the closepacked concave structure with the period of about 3.3 μm can be fabricated on the silicon surface under special parameters (10× focusing lens, laser power of 25 mW, exposing time of 30 s) by loading the phase of 4facet pyramid lens with the base angle of 2°; the formed structure shows good effect of antireflection; its transmission at the near infrared band of 1.2~2 μm enhances 11.5% in comparison with the polished silicon.
贺锋涛, 周强, 杨文正, 龙学文, 白晶, 程光华. 飞秒激光多光束干涉光刻硅表面减反微结构[J]. 光子学报, 2013, 42(5): 515. HE Fengtao, ZHOU Qiang, YANG Wenzheng, LONG Xuewen, BAI Jing, CHENG Guanghua. Femtosecond Laser Multibeam Interference Lithography Antireflective Microstructure on Silicon Surface[J]. ACTA PHOTONICA SINICA, 2013, 42(5): 515.