Effect of stored elastic energy on phase content of ion assisted deposited boron nitride films

Boron nitride films with a different amount of the cubic phase up to 40% have been prepared by radio frequency plasma assisted pulsed laser deposition. By a theoretical analysis of the film formation, which focuses on the stored elastic energy of the film, the cubic boron nitride (cBN) volume fraction experimentally observed has been modelled successfully. The comparison with the experiment shows that the change of the stored elastic energy with the cBN volume fraction determines the final cBN content in the film. The model presented predicts a window for cBN film formation depending on initial film stress. This can explain the often found tight range of process parameters for cBN film synthesis.