【摘要】 用La B6灯丝200 kV高分辨透射电镜拍摄了有小角晶界的3C-Si C/(001)Si薄膜的[1ˉ10]高分辨电子显微像.用像解卷技术把本不直接反映晶体结构的实验像转化为结构像.首先,从完整区的结构像中分辨开间距仅为0.109 nm的Si和C原子柱;随后按赝弱相位物体近似像衬理论,分析像衬随晶体厚度的变化规律,辨认出Si和C原子;进而在原子水平上得出小角晶界附近两个复合位错的核心结构,构建了结构模型并计算了模拟像.实验像与模拟像的一致程度验证了结构模型的正确性.于是,在已知完整晶体结构的前提下,仅从一帧实验高分辨像出发,推演出原子的种类和位错核心的原子组态.还讨论了3C-SiC小角晶界的形成与晶界附近出现复合位错的关系.更多还原

【Abstract】 [1ˉ10] images are taken for 3C-SiC/(001)Si hetero epitaxial films containing small-angle grain boundaries by using a 200 kV La B6 filament high-resolution transmission electron microscope.Deconvolution processing is performed to transform the experimental images which do not represent intuitively the projected crystal structure into structure images.First,Si and C atomic columns with a distance of 0.109 nm are resolved in a perfect structure image region,and then recognized from each other by analyzing the image contrast change with sample thickness based on the pseudo-weak phase object approximation.Subsequently,two complex dislocation cores located in the vicinity of small-angle grain boundaries are obtained at an atomic level,and the atomic structure models are constructed and confirmed by matching the experimental images with the simulated ones.Hence,the atomic configurations of dislocation cores are derived from only a single experimental image with the average structure of perfect crystal known in advance.The formation of small-angle grain boundaries in 3C-SiC/Si with the occurence of complex dislocations in their vicinity is discussed.更多还原