OBSERVATION OF GROWING KINETICS OF SILICON PARTICULATES IN SILNAE PLASMAS

采用射频放电调制技术和两种激光散射技术相结合的新方法，对硅烷等离子体中微粒的生长过程和行为进行了实验研究。所得结果总结如下：颗粒倾向于在电极附近的等离子体/鞘层边界周围持续存在，尤其是射频电极；较大的颗粒存在于靠近射频电极的较低空间电位区域；rf通电后1 ~ 2 s，颗粒尺寸和密度分别达到60 ~ 180 nm和10^8 ~ 10^9 cm^<-3>。与薄膜沉积速率相比，颗粒生长速率非常高，这可以通过考虑正离子和/或自由基通量的贡献来解释。微粒在边界周围的捕获可以用施加在微粒上的静电力和离子阻力的平衡来解释。还揭示了粘性力对微粒的影响以及射频调制放电的微粒抑制机制。

Growing process and behavior of particulates in a silane plasma are experimentally studied using a new method combined an rf discharge modulation technique with two laser light scattering techniques. The obtained results are summarized as follows: particulates tend to be sustained around plasma/sheath boundaries near electrodes, especially the rf electrode; larger particulates exist in a lower space potential region near the rf electrode; particulate size and density amount to 60-180 nm and 10^8-10^9 cm^<-3> in 1-2 s after the rf-power-on. The particulate growth rate, being very high compared to a film deposition rate, can be explained by taking into account the contribution of positive-ion and/or radical fluxes. The particulate-trapping around the boundary can be explained by balance between electrostatic force and ion drag force exerting on a particulate. An effect of viscous force on a particulate and a particulate suppression mechanism for rf modulated discharges are also revealed.