非平衡磁控溅射DLC薄膜应力研究

Study of DLC films residual stress by unbalanced magnetron sputtering technology

类金刚石(DLC) 薄膜可用作红外增透保护膜,高的薄膜残余应力造成薄膜附着力下降是目前应用中存在的主要问题之一.本文从DLC薄膜作为红外增透保护膜的需求出发,采用非平衡磁控溅射技术生长DLC薄膜.实测了薄膜的残余应力,分析研究了薄膜残余应力在不同工艺条件下的变化情况.探讨了薄膜残余应力与薄膜厚度、光学透过率、离子能量、沉积速率以及能流密度之间的关系.研究结果表明,薄膜残余应力平衡值在0.9～2.2GPa之间,相应的单面镀膜样片的透过率在4μm波长处为69% ～ 63%,随工艺的不同而变化.工艺优化后薄膜残余应力显著下降.硅基底上薄膜与基底剥离的力的临界值大于2160GPa·nm,最大薄膜厚度≥ 2400nm;锗基底上最大薄膜厚度≥ 2000nm,可以满足整个红外波段的需求.

Diamond-like carbon （DLC） can be applied in optical devices for infrared antireflection and mechanical protection because of its excellent optical and mechanical properties. Adhesion of DLC on optical devices is a current research topic. This paper discusses the residual stress of DLC films deposited by using an unbalanced magnetron sputtering method as a function of deposition parameters. The dependence of the residual stress on the film thickness, infrared transmittance, ion energy, deposition rate is showed, and ion flux. Stress of the DLC films varies between 0.9 and 2.2 GPa, corresponding to the infrared transmittance at 4μm between 69 and 63% for single-side coated silicon samples. The critical peeling force is more than 2160GPa.nm between the film and silicon samples. The allowed maximum value for thickness is more than 2400nm on the Si samples and 2000nm on the Ge samples.