Characterization of ion species of silicon oxide films using positive and negative secondary ion mass spectra

Abstract Secondary ion species of silicon oxide films have been investigated using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Characterization of thermally grown SiO 2 films on silicon has been performed. A diagram showing secondary ion spectra of SiO 2 films in both positive and negative polarities indicates the pattern of change in polarities and intensities of ion species from SiO + to Si 5 O 11 − . The ions mostly change from positive to negative polarity between Si n O 2 n −1 and Si n O 2 n . Ion peaks with the strongest intensities in the respective cluster ions correspond to the Si n O 2 n +1 negative ion. Intensities of ion species of Si n O 2 n +2 appear negligibly small. Ion species of Si 3 O + , Si 3 O 2 + and Si 3 O 3 + have been found at the interface between silicon and SiO 2 films. The intensity patterns of these ion species compared to those of SiO 2 films indicate that most of these species are not emitted from the SiO 2 films, but likely from the SiO structures.