MODIFICATION OF SURFACE CONDITION AND IRRADIATION EFFECTS OF SYNCHROTRON-RADIATION ON PHOTOEXCITED ETCHING OF SIC

Photoexcited etching of SiC him by synchrotron radiation excitation was investigated from both measurements of total electron yield (TEY) spectra and dependence of the etch rate on irradiated photon energy. We found from TEY spectra that the content of Si near the surface was decreased and that of C was increased upon exposing the SiC surface to reactive species. In the etching experiment with changing irradiated photon energy, we also found that the etch rate showed a photon energy dependence similar to that of photoabsorption of SiC. We concluded that photoexcited etching of SiC was realized based on the progress of the etching of the irradiated region being closely related to the photoabsorption of constituent elements of SiC, and by the slight etching of the nonirradiated region covered by the C-rich fluorinated layer. (C) 1995 American Vacuum Society.