By using thermal H etching or a microwave-powered H plasma for ex situ preparation, a (v3 x v3)R30º reconstruction could be prepared on the {00▪1}-oriented hexagonal surfaces of 4H- and 6H-type samples. The structures were determined by using Auger electron spectroscopy and quantitative low-energy electron diffraction. The surfaces of both orientations were found to be terminated by a monolayer of oxide, whose bond angles and bond lengths agreed with those of bulk SiO2. This adlayer strongly passivated the surfaces. The reconstruction was stable in air, and to annealing at up to 1000C in ultra-high vacuum. Due to the epitaxial relationship, the adlayer could serve as a seed for the growth of crystalline SiO2 and therefore permit the formation of high-quality silica/SiC interfaces.

Silicate Monolayers on the Hexagonal Surfaces of 4H- and 6H-SiC. J.Bernhardt, J.Schardt, U.Starke, K.Heinz: Materials Science Forum, 2000, 338-342, 383-6