2m大口径RB-SiC反射镜的磁控溅射改性

Surface modification of 2 m RB-SiC substrate by magnetron sputtering

为了消除RB-SiC反射镜直接抛光后表面存在的微观缺陷,降低抛光后表面的粗糙度,提高表面质量,针对大口径SiC的特性,选择Si作为改性材料,利用磁控溅射技术对2m量级RB-SiC基底进行了表面改性。在自主研发的Φ3.2m的磁控溅射镀膜机上进行基底镀膜,利用计算机控制光学成型法对SiC基底进行了抛光改性。实验结果表明,改性层厚度达到15μm;在直径2.04m范围内,膜层厚度均匀性优于±2.5%;表面粗糙度由直接抛光的5.64nm(RMS)降低到0.78nm。由此说明磁控溅射技术能够用于大口径RB-SiC基底的表面改性,并且改性后大口径RB-SiC的性能可以满足高质量光学系统的要求。

In order to eliminate the surface microdefect after the direct polishing of RB-SiC substrate,reduce the surface roughness and increase the surface quality,Si was selected as the modified material based on the features of large aperture SiC,where a 2 m-level RB-SiC substrate was modificated by using the magnetron sputtering technology.The silicon film was deposited by a developed Φ3.2 m magnetron sputtering coating machine,and the SiC substrate was polished and modificated based on the computer control optical molding method.The result indicates that the thickness of modified level reaches 15μm;the thickness uniformity of the film level is better than±2.5% within the diameter of 2.04 m;the surface roughness decreases from 5.64 nm（RMS）to 0.78 nm.Therefore a the magnetron sputtering technology can be used in the surface modification of the large aperture RB-SiC,and the performance of the modificated RB-SiC substrate can meet the requirements of high-quality optical systems.