The elastic constants of sputtered aluminum nitride films

Abstract
Brillouin light scattering has been used for determining the five independent elastic constants of polycrystalline AlN films grown by DC magnetron sputtering on Si/sub 3/N/sub 4/ coated (100)-Si substrates. The elastic constants c/sub 66/ and c/sub 11/ have been selectively determined from detection of the shear horizontal mode and of the longitudinal mode travelling parallel to the film surface, respectively. The three remaining elastic constants, namely c/sub 13/, c/sub 33/ and c/sub 44/, have been obtained from detection of the Rayleigh surface mode and of the longitudinal bulk wave propagating at different angles from the surface normal. The values of the elastic constants of these sputtered AlN films exhibit an appreciable dependence on the microstructural properties of the films, which are strongly affected by the deposition conditions. However, they are rather close to those previously determined in epitaxial AlN films grown at high temperature by MOCVD.