Heteroepitaxial thin films of cubic silicon carbide (3C-SiC) on silicon offer a promising platform for leveraging the properties of SiC, such as wide bandgap, high mechanical strength, and chemical stability on a silicon substrate. Such heteroepitaxial films also attract considerable interest as pseudosubstrates for the growth of GaN as well as graphene on silicon wafers. However, due to a substantial lattice mismatch, the growth of 3C-SiC on silicon leads to a considerable amount of stresses, defects, and diffusion phenomena at the heterointerface. We show here that the extent of such interface phenomena and stresses is so large that, after patterning of the SiC, a massive sublimation of the silicon underneath the SiC/Si interface is promoted via a high-temperature anneal, either in high or medium vacuum ambient. A micrometer-thick air gap can be formed below the SiC structures, making them suspended. Hence, the described approach can be used as a straightforward methodology to form free-standing silicon carbide structures without the need for wet or anisotropic etching and could be of great interest for devices where suspended moving parts are needed, such as micro- and nanoelectromechanical systems.

中文翻译：

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通过大规模硅升华在硅微结构上制造自支撑碳化硅

硅上的立方碳化硅 (3C-SiC) 异质外延薄膜为利用 SiC 的特性提供了一个有前途的平台，例如宽带隙、高机械强度和硅衬底上的化学稳定性。这种异质外延薄膜作为用于在硅晶片上生长 GaN 和石墨烯的伪衬底也引起了相当大的兴趣。然而，由于大量晶格失配，3C-SiC 在硅上的生长会导致异质界面处出现大量应力、缺陷和扩散现象。我们在这里表明，这种界面现象和应力的程度如此之大，以至于在对 SiC 进行图案化后，通过高温退火在高真空或中真空中促进了 SiC/Si 界面下方的硅的大量升华周围。可以在 SiC 结构下方形成微米厚的气隙，使它们悬浮。因此，所描述的方法可以用作一种直接的方法来形成独立的碳化硅结构，而无需湿法或各向异性蚀刻，并且对于需要悬挂移动部件的设备（例如微和纳米机电系统）可能具有重要意义。 .