挖坑效应对球形夹具下电子束蒸发沉积薄膜厚度均匀性的影响

厚度均匀性是薄膜制备过程中不可忽视的薄膜特性,厚度不均匀会导致薄膜成品率降低.熔融性比较差的镀膜材料在蒸发过程中以直接气化为主,挖坑效应比较明显.此时,在分析薄膜厚度均匀性时,蒸发源发射特性不随时间变化的假设不再合理.细分蒸发源为无数个小的薄板蒸发源,建立了镀膜材料出现挖坑效应时薄膜厚度均匀性的分析模型.结果表明,在所选镀膜机结构参数下,挖坑效应对薄膜厚度均匀性影响明显;但挖坑效应并不总导致薄膜厚度均匀性变差,设计合适的镀膜室结构以及薄膜制备工艺参数,可借助挖坑效应在一定程度上改善薄膜厚度均匀性.采用易于出现挖坑效应的材料作为镀膜材料时,该研究对设计薄膜沉积工艺参数具有指导性意义.

Influence of Digging Effect on Films Thickness Uniformity for Electron Beam Evaporating onto Sphere Jig

Thickness uniformity can't be ignored in films preparation. Thickness ununiformity will cause low yield film production. Materials without good melting property will not be melted and digging effect will exhibit evidently when electronic beam irradiating on it. In this case, the assumption that emission characteristics of evaporation source is invariable adopted in other papers can't be satisfied any more. Considering that the evaporation source can be thought as containing lots of small plane evaporation source, a model for analyzing the influence of digging effect on films thickness uniformity has been established accordingly. Theoretical results reflect that the digging effect can affect thickness uniformity of films evidently. Digging effect doesn't always cause thickness ununiformity of films. By designing appropriate configuration of the vacuum chamber and adopting appropriate parameters of technics, the thickness uniformity of films even can be improved to a certain extent by virtue of digging effect.