MICRODIFFRACTION STUDIES OF NANOCRYSTALLINE NITRIDE FILMS

The structure of boron nitride and titanium-boron nitride films has been investigated by transmission electron microscopy using microdiffraction techniques. Nearly stoichiometric BN films were produced by RF sputtering and ion beam assisted deposition. They consisted of predominantly cubic nanocrystallites in a quasicrystalline matrix of hexagonal structure. The mean crystallite diameter of the cubic phase was 10-15 nm in the sputtered films and about half this in the ion beam deposited material. Microarea diffraction studies confirmed that the broadening seen in continuous electron diffraction rings originated from discrete crystallites. Recrystallization and secondary phase nucleation occurred in sputter deposited Ti-BN multilayers as a result of thermal annealing and room temperature ageing. Microdiffraction indicated the presence of TiN and a Ti-B-N solid solution but Ti2N, which has been observed in Ti-TiN multilayers, was not found.