Observation of a 6x6 superstructure on 6h-SiC (0001) by reflection high energy electron diffraction

Abstract

A 6 X 6 reconstruction consisting of a silicon-rich phase has been observed on 6H-SiC (0001) after annealing a silicon-enriched 3 X 3 6H-SiC (0001) surface at 900°C. Our results show that the 6 X 6 reconstruction obtained is a long-range reconstruction and not a psuedoperiodic structure due to incommensurately adsorbed graphite honeycombs as suggested previously. We propose that the 6 X 6 structure arises from the absence of consecutive tetrahedral clusters in a tetrahedral cluster array with 3 X 3 periodicity. Annealing the 6 X 6 structure further at 1200°C results in a carbon-rich 6 √3 X 6 √3 R 30 structure. © 2000 American Institute of Physics.