INTERNAL-STRESS AND STRAIN IN HEAVILY BORON-DOPED DIAMOND FILMS GROWNBY MICROWAVE PLASMA AND HOT-FILAMENT CHEMICAL-VAPOR-DEPOSITION

The internal stress and strain in boron-doped diamond films grown by m icrowave plasma chemical vapor deposition (MWCVD) and hot filament CVD (HFCVD) were studied as a function of boron concentration. The total stress (thermal+intrinsic) was tensile, and the stress and strain incr eased with boron concentration. The stress and the strain measured in HFCVD samples were greater than those of MWCVD samples at the same bor on concentration, The intrinsic tensile stress, 0.84 GPa, calculated b y the grain boundary relaxation model, was in good agreement with the experimental value when-the baron concentration in the films was below 0.3 at.%. At boron concentrations above 0.3 at.%, the tensile stress was mainly caused by high defect density, and induced by a node-blocke d sliding effect at the grain boundary. (C) 1996 American Institute of Physics.