Soft X-ray photoemission study of the silicon-fluorine etching reaction

High resolution soft X-ray photoemission spectra of Si(111) surfaces subjected to steady-state etching are reported. The reaction is shown to proceed via the formation of a thick, highly fluorinated reaction layer, dominated by trifluorosilyl moieties. In addition, SiF4, the major reaction product has been observed in the spectra, indicating that it may be trapped within the reaction layer. The implications of these measurements for previously proposed reaction mechanisms are discussed. © 1986.