Chemically vapor deposited (CVD) diamond films are of interest for a wide range of applications. These films are in a state of stress generated during deposition and cooling process. Highly stressed CVD diamond films are undesirable for most applications. The objectives of this study are to understand the origin of stress in CVD diamond films and to find ways to reduce this stress.
The residual stress in diamond films deposited on Si by hot-filament CVD has been investigated by x-ray diffraction technique. In diamond films deposited in this experiment. both total stress and intrinsic stress were tensile stress. Non-diamond phase carbon incorporated in diamond film causes compressive stress. Diamond film which is composed of very small grains, is in a state of large tensile stress. By increasing substrate thickness and by placing a bias between substrate and filament, the tensile stress generated during deposition process can be reduced. In case of placing a bias, it seems that the reduction of tensile stress is caused by formation of SiC layer at diamond/Si interface.
