PECVD制程中磷烷轻掺杂N+A-SI成膜稳定性的研究

Study on The Stability of Lightly Doped Phosphine N+A-SI Film Formation In PECVD Process

为解决G8.5世代线PECVD制程中磷烷轻掺杂N+A-SI成膜中频繁出现反射功率超过3000 W导致的沉积中断,研究了磷烷流量、RF Generator的匹配特性及RFoffset的电极间距对磷烷轻掺杂N+A-SI成膜中最大反射功率的影响,实验结果表明,在电极间距为20.875~21.875 mm之间进行RFoffset可显著降低磷烷轻掺杂N+A-SI成膜中的最大反射功率至3000 W以内,保证磷烷轻掺杂N+A-SI成膜过程的稳定,且该方法可有效地解决此问题,而提高磷烷流量及使用匹配特性较好的RF Generator解决该问题均存在一定的局限性。

We experimentally addressed herein the common deposition interruption problem in synthesis of lightly PH3-doped a-Si:H(N+A-SI) coating,an Ohm contact material for fabrication of Thin Film Transistor-Liquid Crystal Display,by plasma enhanced chemical vapor deposition.The influence of the phosphine(PH3) flow-rate,electrode-distance and characteristics of RF power supply on the largest reflected power was investigated.The results show that the electrode-distance significantly affected the Max reflected power.So,the electrode-distance should be slowly decreased,0.25 mm at a step,to somewhere in 20.875~21.875 mm range depending on the specific situation.Test result show the optimized electrode-distance is capable of keeping the largest reflected power below 3000 W and of effectively solving the deposition interruption problem.