High spatial resolution extended energy loss fine structure investigations of silicon dioxide compounds

The near edge fine structure of the silicon L2,3 edge from Si, SiO2 and SiSiO2 interfaces and the extended energy loss fine structure of the oxygen K-edge from SiO2 and SiSiO2 are studied by means of parallel detection EELS with high spatial resolution scanning transmission electron microscopy. The “fingerprint” technique using the specific characteristics of the Si L2,3 edges in Si, SiO2 and SiSiO2 interfaces is used to distinguish between spectra obtained from different areas. The EXELFS analysis of the oxygen K-edge implies that the OSi bond length is slightly larger in the SiSiO2 interface than in SiO2. The comparison of the EXELFS amplitudes provides a means to observe the differences in coordination numbers and disorder parameters. The results are discussed and compared with data obtained using other techniques.