Large distortion of microcrystalline cubic boron nitride measured by X-ray diffraction

Cubic boron nitride (c-BN) film synthesized by bias sputtering was studied using X-ray diffraction. The diffraction profile analysis indicated that the c-BN film consisted of microcrystals with apparent crystal sizes of about. 34+/-4 Angstrom. Furthermore, it was found that the lattice of microcrystals was distorted by elongation of over Ira toward the film surface direction. This variation could he caused by residual compressive stress lying in the film plane. The residual compressive stress mas estimated to be of the order of 10(11) dyne/cm(2) using elastic theory.