Surface distribution of stress state and diamond phases in [100] oriented diamond films

Stress distribution and diamond phases in polycrystalline diamond film have been investigated by micro-Raman spectroscopy. Intensity, lineshape and pe ak position of the diamond Raman line largely change on the film surface, p articularly if grain center and grain boundary regions are compared. Wherea s in the center of the grains the characteristic diamond Raman line is obse rved, close to grain boundaries an additional feature at 1326 cm(-1) is det ected. Such a Raman component may be related to the presence of hexagonal m icrophases formed by a defect-induced symmetry modification of the diamond lattice. Grain boundaries appear also to be affected by a strongly anisotro pic stress, which induces a frequency shift and splitting of the Raman peak . Stress configurations compatible with the experimental observations are p roposed and discussed.