利用后通硅烷法优化高速微晶硅薄膜的纵向结构

Improved homogeneity of microcrystalline thin film by delayed silane method

本文采用四极杆质谱对高速沉积硅薄膜过程中硅烷浓度的变化情况进行了在线监测,针对反应过程中的反向扩散现象进行了研究.结合硅烷耗尽模型的计算,对反应气体的馈入方法进行了优化.结果表明,适当的调整硅烷气体与等离子体起始放电时刻的时间差,可以有效的控制反应过程中硅烷浓度,特别是放电开始瞬间时的条件,从而改善器件的界面特性以及薄膜厚度方向上的纵向结构均匀性.

With help of quadruple spectrometry, we monitored transient changing of silane concentration （Cp） during microcrystalline thin film （uc-Si：H） deposition at high rate, especially the initial stage when back diffusion always occurred. Based on the model of transient depletion of silane, we calculated the delayed time at different pressure and total gas flow rate. And the optimized delayed time leading to good homogeneity from theory calculation is well agreed with the experiment result. It was shown that the time lag affects the starting Cp, which could be the reason of improved homogeneity.