以衬底温度和射频(RF)功率为调控晶化多晶硅薄膜的氢等离子钝化处理工艺的参数,借助发射光谱(OES)全程实时探测以及对氢化处理后薄膜的傅里叶变换红外吸收谱(FTIR)的分析,通过钝化前后薄膜电性能相对照,探讨工艺优化的微观机理。对于LPCVD为晶化前驱物SPC晶化的样品,氢等离子体中的Hβ和Hγ基元对氢钝化处理起主要作用。硅薄膜氢化处理后膜中的氢以Si-H或Si-H2的形态大量增加。随氢化处理的温度升高,促使Hβ和Hγ以更高的动能在表面移动并进入薄膜内与硅悬挂键键合。只有提供足够的动能才能有效改善多晶硅微结构(R降低),使霍尔迁移率得以增大;样品在足够高的衬底温度下,只需较低功率即能产生所需数量的Hβ和Hγ等离子基元对样品予以钝化。降低功率,能有效降低I2100、继而减小R,从而减少对薄膜的轰击和刻蚀,有利提高电学性能。实验中样品氢化处理较优化的条件为550 ℃,10 W,其霍尔迁移率提高了43.5%。

The microscopic mechanism of the hydrogen passivation was studied by investigating the effect of substrate temperature and RF power on the performance of poly-Si using OES and FTIR. We found that Hβ and Hγ played a major role on hydrogen passivation which used LPCVD as a precursor crystallized by SPC. The intensity of Si-H or Si-H2 in poly-Si increased drastically after passivation. Within a certain temperature range, the higher the substrate temperature was, the more radicals could attach themselves to the dangling bonds, while improving the poly-Sis microstructure parameter (R) and hall mobility. Because affluent hydrogen radicals RF power could be generated to passivate poly-Si even at low power, when the RF power was reduced, I2100 and R was lowered and new defects were reduced by bombardment and etching effects, improving the performance. Passivation process is also optimized. The hall mobility is improved by 43.5% at 550 ℃ 10 W.