SiCl_4/H_2辉光放电等离子体中电子特性的在线检测

Experimental study of electron characteristics of SiCl_4/H_2 glow discharge plasma

SiCl4/H2混合气体被公认为低温沉积纳米晶以及多晶硅薄膜最具潜力的气源之一。首次利用加热可调谐Langmuir探针对等离子体增强化学气相沉积系统中的SiCl4/H2放电等离子体的电子浓度和电子平均能量进行了在线检测,并分析了电子特性随系统各参数:气体压强、射频功率及氢稀释度RH的变化规律。实验结果表明:随着气体压强的升高,电子浓度不断增大而电子平均能量不断减小;增大射频功率或减小氢稀释度RH,电子浓度和电子平均能量都相应增大。此外,并对实验结果进行了定性或半定量分析。本研究工作将有助于更好地理解SiCl4/H2放电机理,改善并优化沉积优质多晶硅薄膜的工艺参数。

SiCl4/H2 mixture gases are investigated as a potential gases source for nc-Si and polycrystalline silicon films growth at low temperatures. In this letter, the electron density and the mean electron energy of SiCl4/H2 discharge plasma in plasma enhanced chemical vapor deposition system are first measured by a heated and tuned Langmuir probe. We analyze the dependence of electron characteristics on the process parameters, such as gas pressure, rf power and hydrogen dilution ratio RH. The experimental results demonstrate that： The electron density increases while the mean electron energy decreases with the increasing gas pressure; Both the electron density and the mean electron energy increase with the increase in rf power; Both the electron density and the mean electron energy increase with the increase in hydrogen dilution ratio RH. Corresponding qualitative or semi-quantitative analytical dependence of electron characteristics on the process parameters agree with the measured results well. This study is used for better understanding the discharge mechanism and optimizing deposition conditions.