石英衬底上大晶粒多晶Si薄膜的制备与结构表征

Fabrication and Structural Characterization of Large Grain Polycrystalline Silicon Films on Quartz Substrates

利用高频感应加热化学气相沉积工艺,以H2稀释的SiH4作为反应气体源,在未抛光的粗糙石英衬底上直接沉积制备了具有均匀分布的大晶粒多晶Si膜。采用扫描电子显微镜、X射线衍射和可见-紫外分光光度计等检测手段,测量和分析了沉积膜层的表面形貌、晶粒尺寸、择优取向与光反射等特性。结果表明,多晶Si膜中Si晶粒的尺寸大小和密度分布不仅与工艺参数有关,而且强烈依赖于衬底的表面状况。1000℃下沉积薄膜的平均晶粒尺寸为～3μm,择优取向为<111>晶向。反射谱测量表明,920℃下制备薄膜的反射率比1000℃下制备的更低,最低值达18.4%,这应归功于前者具有更大的表面粗糙度。

Uniform large grain polycrystalline silicon films with grain size of ～3 μm were directly deposited on the unpolished quartz substrate by high frequency induced heating chemical vapor deposition system and using H2-diluted SiH4 as reactive gas.Scanning electronic microscopy,X-ray diffraction and reflection measurement were used for the measurement of the surface morphologies,crystallinity and optical characteristics.The results show that the deposited polycrystalline silicon films possess good crystallinity and preferred orientation of 111.The reflectivity of films deposited at 920 ℃ is lower than that under 1000 ℃ when wave length range from 300 to 1465 nm with the minimum of 18.4%,which is attributed to the former has a larger surface roughness.