STUDY OF STRESS IN MICROWAVE PLASMA CHEMICAL-VAPOR-DEPOSITED DIAMOND FILMS USING X-RAY-DIFFRACTION

Residual stress in polycrystalline diamond films has been studied. Uni form polycrystalline diamond films were deposited on 3.0in. diameter s ilicon substrates in a microwave plasma chemical vapor deposition (MPC VD) system. The effects of CH4/H-2 ratio, pressure, and power Variatio n on film stress were investigated. The macro-stress, or uniform stres s, in the films was measured using the X-ray diffraction (XRD) d-sin(2 ) psi technique. In general, [220]-oriented films exhibited tensile st ress and [111]-oriented films were in compression. The micro-stress, o r non-uniform stress, calculated from diffraction peak broadening, was observed to be tensile for all samples. Films of relatively small gra in size and [220] orientation showed both the highest micro-stress and the highest macro-stress. Film morphology was analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM), while th e film texture was studied using XRD. Significant non-diamond carbon w as incorporated in [220]-oriented diamond as estimated from the intens ity of the broad 1580 cm(-1) peak in the Raman spectra. Much less non- diamond carbon was detected in [111]-oriented diamond films. Good corr elation between film morphology and measured stress was observed.