Elastic-filtered electron diffraction for structure determination of AlN specimen

On a transmission electron microscope equipped with a serial energy-loss sp ectrometer, a post-specimen on-line scanning device has been adapted, permi tting elastic or inelastic filtered intensity profiles in the images or sel ected area diffraction patterns to be recorded. From elastically filtered d iffraction pattern intensity profiles, the nearest-neighbour correlation di stances and coordination numbers in amorphous and polycrystalline samples c an be obtained. The properties of the device have been tested on a pure pol ycrystalline aluminium sample, for which the accuracy of the interatomic di stance determination is 0.03 Angstrom in the range 0 to 12 Angstrom. This t echnique has been used to study the relation between the nanostructure of t hin amorphous and polycrystalline films of aluminium nitride and the deposi tion process.