Hydrogen etching of a 4H-SiC(0001) surface at a moderate temperature of 1200 °C with molecular hydrogen gas was investigated to obtain enough flat and clean surface for large-scale high-quality epitaxial graphene synthesis. We found after a prolonged hydrogen etching that micro scratches, large depressions, and contaminations produced on the wafer in the manufacturing process disappeared and that a periodic array of atomic steps appeared, maintaining initial flat surface morphology. One hour of etching with a flow of 1.0 l/min was the optimum condition to obtain a flat and clean SiC surface in the present study. Using such surfaces, we were able to synthesize the so-called zero layer graphene by thermal annealing in ultrahigh vacuum.

中文翻译：

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碳化硅（0001）表面在中温下的氢蚀刻

研究了在 1200°C 的中等温度下用分子氢气氢蚀刻 4H-SiC(0001) 表面以获得足够平坦和清洁的表面，用于大规模高质量外延石墨烯合成。我们发现，经过长时间的氢蚀刻，在制造过程中在晶片上产生的微划痕、大凹陷和污染消失了，并且出现了周期性的原子台阶阵列，保持了初始平坦的表面形态。在本研究中，以 1.0 l/min 的流速蚀刻 1 小时是获得平坦干净的 SiC 表面的最佳条件。使用这样的表面，我们能够通过超高真空中的热退火合成所谓的零层石墨烯。