利用x射线小角散射技术研究微晶硅薄膜的微结构

采用x射线小角散射（SAXS）技术研究了由射频等离子体增强化学气相沉积（rf-PECVD）、 热丝化学气相沉积(HWCVD)和等离子体助热丝化学气相沉积(PE-HWCVD)技术制备的微晶硅（ μc-Si:H）薄膜的微结构.实验发现，在相同晶态比的情况下，PECVD沉积的μc-Si:H薄膜微 空洞体积比小，结构较致密，HWCVD沉积的μ-Si:H薄膜微空洞体积比大，结构较为疏松，PE -HWCVD沉积的μc-Si:H薄膜，由于等离子体的敲打作用，与HWCVD样品相比，微结构得到明 显改善.采用HWCVD二步法和PE-HWCVD加适量Ar离子分别沉积μc-Si:H薄膜，实验表明，微结 构参数得到了进一步改善.45°倾角的SAXS测量显示，不同方法制备的μc-Si:H薄膜中微空 洞分布都呈各向异性.红外光谱测量也证实了SAXS的结果. 关键词： 微晶硅薄膜 微结构 微空洞 x射线小角散射

The microstructure of hydrogenated microcrystalline silicon thin films studied by small-angle x-ray scattering

The microstructures of hydrogenated microcrystalline silicon (μc-Si:H) thin fil ms, prepared by plasma-enhanced chemical vapor deposition (PECVD), hot wire CVD( HWCVD) and plasma assisted HWCVD (PE-HWCVD), have been analyzed by the small ang le x_ray scattering(SAXS) measurement. The SAXS data show that the microstructur es of the μc-Si:H films display different characteristics for different deposit ion techniques. For films deposited by PECVD, the volume fraction of micro-voids and mean size are smaller than those in HWCVD sample. Aided by suitable ion-bom bardment, PE-HWCVD samples show a more compact structure than the HWCVD sample. The microstructure parameters of the μc-Si:H thin films deposited by two-steps HWCVD and PE-HWCVD with Ar ions are evidently improved. The result of 45° tilti ng SAXS measurement indicates that the distribution of micro-voids in the film i s anisotropic. The Fouriertransform infrared spectra confirm the SAXS data.