Annealing effect on surfaces of 4H(6H)SiC(0001)Si face

We have investigated 4H- and 6HSiC(0001)Si faces prepared by heat treatment using Auger electron spectroscopy (AES), low energy electron diffraction (LEED) and scanning tunneling microscopy (STM) in ultra high vacuum (UHV). The following were elucidated: 3 × 3 reconstruction was observed on the surface prepared at ∼ 1000°C, while 6 × 6 superstructure was observed for a specimen prepared at ∼ 1200°C. The 6 × 6 reconstruction can be explained as a moiré pattern produced by a graphite layer sitting on top of SiC surface. Also AES p-p height ration of Si(LVV)C(KLL) decreased at a higher temperature for 4HSiC than for 6HSiC, which could be due to the fact that the bond strength of 4HSiC is more than that of 6HSiC.