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Hydrogen-gas etching of a 6H-SiC(0001) surface and subsequent annealing in nitrogen atmosphere leads to the formation of a silicon oxynitride (SiON) epitaxial layer. A quantitative low-energy electron diffraction analysis revealed that the SiON layer has a hetero-double-layer structure: a silicate monolayer on a silicon nitride monolayer via Si-O-Si bridge bonds. There are no dangling bonds in the unit cell, which explains the fact that the structure is robust against air exposure. Scanning tunneling spectroscopy measured on the SiON layer shows a bulk SiO2-like band gap of approximately 9 eV. Great potential of this new epitaxial layer for device applications is described.

An electron beam (EB) irradiation effect on the Si(001)-c(4 x 2) surface was investigated by using low-energy electron diffraction. Quarter-order spots become dim and streaky by EB irradiation below approximately 40 K, indicating a disordering in the c(4 x 2) arrangement of buckled dimers. A quantitative analysis of decreasing rates of the spot intensity at various conditions of beam current, beam energy, and substrate temperature leads to a proposal for a mechanism of the disordering in the buckled-dimer arrangement in terms of electronic excitation, electron-phonon coupling, and carrier concentration.