热丝CVD法低温制备的多晶硅薄膜质量对衬底依赖性的研究

The quality dependence on substrates for poly-Si thin films deposited by HWCVD at low temperature

以SiH4和H2作为反应气体,采用HWCVD的方法分别在石英玻璃、AZO、Si(100)和Si(111)衬底上制备了多晶硅薄膜。利用X射线衍射(XRD),拉曼(Raman)光谱和傅里叶红外(FT-IR)吸收光谱研究了不同衬底对多晶硅薄膜的择优取向、晶化率和应力的影响,用SEM观察了多晶硅薄膜的表面形貌。研究发现在4种衬底上生长的多晶硅薄膜均为(111)择优取向。单晶硅片对多晶硅薄膜有很强的诱导作用,并且Si(111)的诱导作用优于Si(100)的诱导作用。AZO对多晶硅薄膜生长也有一定的诱导作用。通过计算薄膜晶态比,得到除以石英为衬底的样品外,其它3种样品的晶态比均在90%以上,尤其以单晶硅片为衬底的样品更高。石英玻璃、AZO和Si(100)上生长的多晶硅薄膜中均存在压应力。

Poly-crystalline silicon thin films were prepared on quartz glass,AZO,Si（100） and Si（111） substrates using SiH4 and H2 by hot wire chemical vapor deposition（HWCVD）.Crystalline fraction,orientation and stress in the films deposited on different substrates were characterized by XRD,Raman spectrum and FT-IR.Surface morphology was observed by SEM.The results show that all the samples are（111） oriented.Si substrates can promote the crystallization of the films deposited on them,and Si（111） substrate has better induction effect than Si（100） substrate.AZO which is（002） oriented also shows induction effect.Raman spectra are fitted and crystalline fraction for all the films are calculated.The result shows that except the film deposited on quartz glass,all the other samples have crystalline fraction above 90%,with especially higher ones for films on Si substrates.There exist compressive stress in the samples except the film deposited on Si（111）.