论文部分内容阅读
本文采用VHF-PECVD技术制备了两个不同硅烷浓度(SC)系列的微晶硅薄膜,通过椭圆偏振技术研究了微晶硅薄膜的微结构和表面粗糙度随沉积时间的变化。实验结果表明:随着薄膜厚度的增加,两个系列硅薄膜的晶化度增加,当薄膜增加到一定厚度时内部开始出现微空洞,这是由于随着薄膜厚度的增加,薄膜晶化度增加,晶粒增大,大晶粒边界之间更容易形成空洞。硅薄膜的表面粗糙层厚度ds与薄膜厚度d满足指数关系:ds~dβ,β为生长指数,与薄膜生长机制有关,当硅烷浓度SC为4%时,β=0.33,对应有限扩散生长模式。硅烷浓度SC为5%时,β=0.52,对应为零扩散随机生长模式。硅烷浓度降低,生长指数β减小,这是由于随着硅烷浓度的降低,氢原子浓度增加,薄膜表面氢覆盖扩大,从而有利于反应前驱物的扩散,因此薄膜表面更为光滑,生长指数β减小。
In this paper, two microcrystalline silicon thin films with different silane concentration (SC) series were prepared by VHF-PECVD technique. The microstructure and surface roughness of microcrystalline silicon thin films were studied by ellipsometry. The experimental results show that with the increase of the film thickness, the crystallinity of the two series of silicon films increases. When the film thickness increases to a certain thickness, micro-cavities begin to appear in the interior. This is due to the increase of the crystallinity of the film as the film thickness increases , Grain size increases, large grain boundaries more easily formed between the hollow. The thickness ds of the silicon film satisfies the exponential relationship with the film thickness d: ds ~ dβ, β is the growth index, which is related to the growth mechanism of the film. When the silane concentration SC is 4%, β = 0.33 corresponds to the limited diffusion growth mode. At a silane concentration SC of 5%, β = 0.52 corresponds to a zero-diffusion random growth mode. Silane concentration decreased, the growth index β decreased, which is due to the silane concentration decreases, the hydrogen concentration increases, the film surface hydrogen coverage expanded, which is conducive to the diffusion of reaction precursors, the film surface is more smooth, the growth index β Decrease