Formation of nitride layers on 6H-SiC surfaces

Abstract

The interaction of nitrogen with differently reconstructed 6H-SiC surfaces and thin Si adlayers on Si-terminated SiC surfaces was investigated. Clean (0001) and (0001̄) surfaces were obtained in ultrahigh vacuum by heating them either in the presence of a Si flux at different temperatures or by annealing. For nitridation, a RF plasma source was used. X-ray photoelectron spectroscopy results reveal the formation of a 9 Å thick silicon nitride surface layer via an anion exchange on bulk-truncated 6H-SiC surfaces at room temperature. The film thickness initially rises with increasing sample temperature during nitrogen exposure up to about 14 Å but decreases for temperatures above 1150 K. In order to obtain thicker nitride layers, we deposited thin Si layers on Si-terminated SiC surfaces.