Study on effect of discharge frequency on particle growth in high frequency plasma.

作为放电频率参数，研究了硅烷射频放电中粒子生长过程的放电频率依赖关系。一系列实验结果表明：在各种放电频率下，粒子在等离子体/鞘边界附近成核和长大；在恒功率下，随着放电频率的增加，快速生长阶段粒子的生长速率降低，但由于密度的增加，在放电开始后更早观察到粒子的生长；-10 nm的粒子密度与离子的密度相当，甚至高于离子的密度，因此几乎是中性的。这些结果不能用常规的热凝聚模型来解释，这表明在10‘S eV以上的高能电子在中性粒子的快速生长过程中起着重要的电离作用。为了正确解释这些实验特征中的大部分，提出了一个粒子凝聚模型。

Discharge frequency dependence of growth processes of particles in silane rf discharges have been studied in a size range above a few nanometers as parameters of discharge frequency. A seies of experiments have given the following results : particles nucleate and grow around the plasma/sheath boundary by the rf electrode for all discharge frequencies ; increasing the discharge frequency under a constant power, a growth rate of particles in the rapid growth phase decreases, while they begin to be observed earlier after the discharge initiation due to the increase in their density ; a density of particles of -10nm in size is comparable to or even higher than that of ions, and hence almost of them are neutral. These results can not be explained by the conventional thermal coagulation model, suggesting that high energy electrons above several 10's eV play an important role to ionize a part of neutral particles in their rapid growth. In order to explain properly most of these exprimental features, a particle coagulation model is proposed.