Crystal growth of 3C-SiC on Si substrates by channel epitaxy method

本文报道了采用通道外延法在Si衬底上生长3C-SiC的异质外延，以减少3C-SiC薄膜中的高密度缺陷和应变。有必要对靠近3C-SiC/Si界面的外延生长进行研究。用Si2(CH3)6（六甲基二硅烷：HMDS）在（111）和（100）硅衬底上生长了3C-SiC层。在sic衬底外延生长初期，每个3C-SiC岛的直径取决于CVD生长的温度。利用“微通道外延”（MCE）形成了三维精细结构。用反应离子刻蚀法制备线和空间结构具有重要意义。线间距是获得良好沟道外延的关键。形成的MCE的结晶度不受成核和生长的控制，呈多晶状。在硅衬底上生长3C-SiC的初始阶段，可以通过严格控制实验参数来改善这一结果。在Si（100）衬底上形成t形图案，这种结构有利于沟道外延。在这种情况下，我们称这种形状为垂直沟道外延。外延层生长在t形区域的顶部，而不是从Si衬底的沟道上生长。碳化是在t型板上获得光滑外延层的关键。一旦脱毛层很好地延伸到t形区域，这些层就会合并到相邻的脱毛层。用透射电镜对聚结区进行了检测。缺陷的湮灭应作详细的研究。

This study reports on heteroepitaxial growth of 3C-SiC on Si substrate with channel epitaxy method in order to reduce the high density of defects and the strain in the 3C-SiC epilayer. It has been necessary to investigate the epitaxial growth close to the 3C-SiC/Si interface. 3C-SiC layer was grown mainly on a (111) and (100) silicon substrates by using Si2(CH3)6 (Hexamathyldisilane : HMDS). The diameter of each 3C-SiC island depended on the temperature of CVD growth at an early stage of epitaxial growth of 3C-SiC on Si substrate.Three-dimensional fine structures were formed by using "micro-channel epitaxy (MCE)". It was important to parepare the line and space structures by Reactive Ion Etching method. Line and space interval is a key to obtain good channel epitaxy. The crystallinity of formed in MCE became like polycrystalline without the control of nucleation and growth. This result may be improved by close control of experimental parameters at initial stage of 3C-SiC grown on Si substrates. T-shape pattern was formed on the Si(100) substrate and this structure was effective to get channel epitaxy. In this case, we call this shape as vertial channel epitaxy. Epitaxial layer was grown on the top of T-shape area not from the channel in the Si substrate. Carbonization was a key to obtain smooth epi-layer on the T-shape plate. Once epilayers extends nicely on the T-shape area, those layers coalescences to neighbor epilayer. Coalescenced region was examine by TEM. Annihilation of defects should be studied in detail.