Hydrogen etching of the SiC(0001) surface at moderate temperature

Hydrogen etching of a 4H-SiC(0001) surface at a moderate temperature of 1200 degrees 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.

Automated summary

Hydrogen etching of 4H-SiC(0001) surface at a moderate temperature was investigated to obtain a flat and clean surface for high-quality epitaxial graphene synthesis. After prolonged etching, scratches, depressions, and contaminations disappeared, and atomic steps appeared, maintaining the initial morphology. The optimum condition for flat and clean SiC surface was one hour of etching with a flow of 1.0 l/min, enabling the synthesis of zero layer graphene by thermal annealing in ultrahigh vacuum.