高氢稀释制备微晶硅薄膜微结构的研究

MICROSTRUCTURES OF THE MICROCRYSTALLINE SILICON THIN FILMS PREPARED BY HOT WIRE CHEMICAL DEPOSITION WITH HYDROGEN DILUTION

采用高氢稀硅烷热丝化学气相沉积方法制备氢化微晶硅薄膜．其结构特征用Ｒａｍａｎ谱，红外透射谱，小角Ｘ射线散射等来表征．结果表明微晶硅的大小及在薄膜中的晶态比χｃ随氢稀释度的提高而增加．而从红外谱计算得到氢含量则随氢稀释度的增加而减少．小角Ｘ射线散射结果表明薄膜致密度随氢稀释度的增加而增加．结合红外谱和小角Ｘ射线散射的结果讨论与比较了不同相结构下硅网络中Ｈ的键合状态．认为随着晶化的发生和晶化程度的提高Ｈ逐渐移向晶粒表面，在硅薄膜中Ｈ的存在形式从以ＳｉＨ为主向ＳｉＨ２转变，即在微晶硅膜中主要以ＳｉＨ２形式存在于晶粒的界面．

AbstractMicrocrystalline silicon thin films were prepared by hot wire chemical vapor deposition with hydrogen dilution. Structures of the films were examined by Raman scattering, Fourier transform infrared (IR) and small angle Xray scattering (SAXS)etc. It is shown that with increasing flow ratio RH=H_2/(H_2+SiH_4) the volume fraction of crystalline increases while the hydrogen content decreases. The result from SAXS indicates that with increasing dilution ratio, the density of the film is increased, which implies the volume fraction of microvoids is reduced. Combining with the data from IR and SAXS, we conclude that SiH_2 vibration mode in hydrogenated microcrystalline silicon thin film is located at the grain boundaries rather than in the internal surface of the micro-voids.