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

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 CF4based plasmas. Valence-band photoemission reveals a band of three fluorine induced features, at binding energies of ~ 11.9, and 14.4 eV. Comparisons with the Si02valence 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. © 1988, American Vacuum Society. All rights reserved.