本征微晶硅薄膜孵化层的深入研究

Further study of the incubation layer in hydrogenated microcrystalline silicon film growth

采用VHF-PECVD技术沉积微晶硅薄膜,获得较高的生长速度,但是薄膜质量较差,这与初始生长过程中生成厚的非晶孵化层关系密切。本研究表明,孵化层的厚度与硅烷浓度、功率密切相关:低的硅烷浓度,能保证成膜过程中氢原子打破弱键的几率,逐层生长现象明显;大的馈入功率,能保证更多氢原子参与成膜反应,减少悬键缺陷。这两方面的优化,最终把孵化层降低到26.55 nm。

Preparation of hydrogenated microcrystalline silicon （μc-Si：H） thin film by VHF-PECVD can reach to a higher growth rate, but a poorer film quality, which is due to the generation of a thick amorphous incubation layer during the initial growth. The research in this paper showed that the thickness of incubation layer is closely related to the silane concentration and input power density. Lower silane concentration can guarantee the probability of hydrogen breaking the weak bond, and thin film obviously exhibits layer by layer growth mechanism. Higher input power could drive more hydrogen atoms to the film surface for growth reaction. Through the optimization of these two conditions, the thickness of incubation layer is decreased to 26.55 nm.