6H-SiC衬底上异质外延3C-SiC薄膜的结构研究

A Structural Investigation of 3C-SiC Film Hetero-Epitaxial Grown on 6H-SiC Substrate

以SiH4和C3H8为反应源,在1250℃下,采用低压热壁化学气相淀积法在6H-SiC衬底上异质外延生长了3C-SiC薄膜.扫描电镜和原子力显微镜测试结果显示,样品表面光滑、无明显岛状结构物质.剖面透射电镜照片显示SiC外延层致密均匀、界面平整,厚度约为50nm.高分辨透射电镜结果显示,衬底与外延层分别为排列整齐的6H-SiC结构和3C-SiC结构,两者过渡平坦、界面处无其他晶型.选区电子衍射花样标定结果再次说明外延薄膜为闪锌矿结构的3C-SiC,计算的晶格常数为0·4362nm.

3C-SiC film was hetero-epitaxial grown on 6H-SiC substrate by the low temperature hot wall chemical vapor deposition method at 1250℃ ,using SiI-L and C3 Ha as gas sources. Results of scanning electron microscopy and atomic force microscopy show that the sample＇s surface is smooth without a visible island structure. The image of the cross-section transmission electron microscopy shows that the compact and uniform SiC epi-layer has a flat interface,and its thickness is about 50nm. High-resolution transmission electron microscopy shows that the substrate and epi-layer are well-arranged 6H-SiC and 3C-SiC structUres, respectively,with a smooth transition and no polytype in the junction. The selected area electron diffraction pattern also shows that the epi-layer is 3C-SiC film with a zinc blende structure,and the calculated lattice constant is 0. 4362nm.