Valence‐band photoemission and electron energy‐loss studies of reactive ion etched silicon dioxide

Abstract

Results are presented for x‐ray photoemission and electron energy‐loss (EELS) measurements of the valence bands and band‐gap region of silicon dioxide fluorinated during reactive ion and plasma etching in CF4 based plasmas. Valence‐band photoemission reveals a band of three fluorine induced features, at binding energies of ∼10.0, 11.9, and 14.4 eV. Comparisons with the SiO2 valence bands and implications for bonding are discussed. Complementary results from EELS are presented along with a discussion of transitions observed in the band gap of etched silicon dioxide. A comparison of samples etched under reactive ion etching conditions with those etched under plasma etching conditions (negligible ion bombardment) indicates that the ion bombarded surfaces exhibit a reduced level of fluorination during steady‐state etching.