An STM observation of the initial process of graphitization at the 6H-SiC(000(1)over-bar) surface

We applied scanning tunneling microscopy (STM) as well as low-energy electron diffraction (LEED) to analyze the initial process of graphitization at 6H-SiC(000 (1) over bar) surfaces. After annealing a 6H-SiC(000 (1) over bar) surface at 1200degreesC, there appeared many domains with a single graphite layer in the STM image. Each graphite domain was azimuthally disordered to each other. Many large and small domains with various periodicities were observed in the STM image taken after annealing the surface at temperatures higher than 1300degreesC. These STM images can be explained as Moire patterns due to different combinations of two graphite layers. In a LEED pattern azimuthally rotated graphite I x 1 spots are observed together with the fundamental 6H-SiC(0001)(1 x 1) spots, in consistent with the STM result.