为解决类金刚石膜内应力极大的问题, 利用很薄的岛状结构锗层与较厚的类金刚石层循环, 设计并制备了具有低内应力的多层类金刚石膜。其中, 类金刚石层为主要功能膜层, 起到硬质保护和光学增透的作用; 而锗层作为缓冲层, 起到缓解纯类金刚石膜内应力过大的问题, 同时由于锗层很薄, 对整个膜层的机械性能和红外特性的影响很小。测试表明, 制备的多层类金刚石膜内应力为2.14 GPa, 比纯类金刚石膜降低了39%, 通过了GJB2485-95《光学膜层通用规范》中的重摩擦测试; 同时, 其纳米硬度仍保持在47 GPa的高水平。该多层类金刚石膜可以作为实际应用的红外窗口保护膜。

Multilayers diamond-like carbon film, which was composed of several thick diamond-like carbon layers and thin germanium island layers, was prepared on the germanium substrate in order to resolve the high inner-stress in the diamond-like carbon film. The diamond-like carbon layers had the main function of protection, and the germanium island layers had the buffer function to reduce the inner-stress in the diamond-like carbon film. Meanwhile, the thicknesses of the germanium layers were very thin, so they had no influence on the mechanical and infrared performances of the whole film nearly. Inner-stress in the multilayers diamond-like carbon film was 2.14 GPa, 39% lower than that of the pure diamond-like carbon film, and the multilayers diamond-like carbon film could pass the friction test stipulated in the GJB2485-95′general specification for optical coatings. The hardness of the multilayers diamond-like carbon kept high hardness of 47 GPa, and had the same surface roughness to the pure diamond-like carbon film. Therefore, the multilayers diamond-like carbon film could be used as practical protective film for infrared window.