Application of nano-diffraction to local atomic distribution function analysis of amorphous materials

A method is proposed for the local atomic distribution function analysis of amorphous materials. This method is based on local halo.-electron diffraction intensity analysis with nano-sized electron probes as small as 25 - 3 nm, taking advantage of the intensity recording with imaging plate. Nano-diffraction and selected area electron diffraction (SAED) patterns from an amorphous SiNx, (x similar to4/3) thin film were taken using a conventional transmission electron microscope operated at 200 kV and recorded on imaging plates. An intensity correction to omit inelastic intensity was made using electron energy-loss Spectroscopy. When a beam-convergence angle is larger than 1 X 10(-3) rad, the Wiener-filter deconvolution method becomes helpful in producing atomic pair distribution functions (PDFs) from the nano-diffraction intensity profiles that are more similar to the PDF from the SAED intensity. This technique was applied to the analysis of local amorphous structures of SiO2 layers formed by an oxygen-ion implantation into single crystal SiC.