渐变反射率镜的设计与制备

按照高斯型渐变反射率镜(GRM)的参数要求,采用了中间层厚度渐变的方案对膜系和掩模板形状进行设计.根据薄膜的实际需求和具体的沉积设备,设计了掩模和掩模切换装置.在一次高真空环境下镀制了渐变反射率镜的所有膜系.采用直接测量的方法,测量了高斯型渐变反射率镜反射率的径向分布.测试结果表明,用这种技术制备的样晶,与设计要求基本一致.分析得出,掩模板形状与精度对镀制结果有影响.随着设计尺寸减小,掩模板对膜料分子的散射作用增强,使样品中心反射率小于设计要求,边缘出现旁瓣.提出了减小基片与掩模板之间的距离和提高膜厚监控的精度的改善方案.

Design and Fabrication of Graded Reflectivity Mirrors

According to the parameter requirement of the graded reflectivity mirror(GRM) with Gaussian profile,the layer structure and the mask pattern were designed by using graded-thickness middle layer.The mask and the mask switchover equipment were designed considering the actual requirement of the thin films and the specific deposit facility.All layers of the graded reflectivity mirror were deposited in one high vacuum environment.Using a direct measuring method,the radial reflectivity distribution of graded reflectivity mirror with Gaussian profile was measured.The measuring results indicate that the graded reflectivity mirror with Gaussian profile prepared with this technique is basically in accordance with the design requirement.Analysis indicates that the mask pattern and accuracy influence the deposit result.The scattering effect of the mask on the material molecules increases with the decrease of the design dimension,the center reflectivity of the sample becomes lower than the design requirement,and the side lobe arises at the edge of the sample.The improving methods are proposed as decreasing the distance between the substrate and the mask,and increasing the monitor accuracy of the layer thickness.