锗衬底表面圆柱形仿生蛾眼抗反射微结构的研制

Study on Bionic Moth-Eye Antireflective Cylindrical Microstructure on Germanium Substrate

采用严格耦合波分析方法研究了长波红外波段锗基底的圆柱形周期阵列仿生蛾眼抗反射微结构的衍射特性,并进行理论分析和模拟仿真验证。重点分析了周期、深度、占空比和整体面型轮廓等参数对微结构抗反射特性的影响,得出具有较好抗反射效果的结构组合参数。采用二元曝光技术和反应离子刻蚀技术在锗基底上制备该亚波长周期微结构。通过热场发射扫描电子显微镜对微结构表面形貌进行表征,并应用红外成像光谱仪在长波红外波段分别对双面抛光锗片、单面微结构和双面微结构进行测试对比,结果显示在8~12μm范围内双面微结构的反射率小于8%,基本达到设计要求。

Based on the rigorous coupled wave analysis method,the diffraction characteristics of bionic moth-eye antireflective cylindrical microstructure is researched at long wave infrared wavelengths.By theoretical analysis and simulation,the effects of the moth-eye microstructure parameters,such as period,depth,filling factor,profile shape in actual manufacturing process on their reflectivity,are discussed.A structure parameters combination is optimized to obtain low reflection.The sub-wavelength period microstructure on germanium substrate is fabricated by binary exposure and reactive ion etching technology.The surface topography is analyzed by thermal field emission scanning electron microscopy,the infrared imaging spectrometer is applied to contrast the germanium wafer with double sides polishing,single-sided and double-sided moth-eye microstructures.The measurement results illustrate that the reflection efficiency of the double-sided microstructures is less than 8% at 8~12μm wavelength,which achieves the design requirements.