THERMAL-CONDUCTIVITY OF DC-PLASMA ASSISTED CHEMICAL-VAPOR-DEPOSITED DIAMOND FILMS

The dc-plasma assisted chemical vapor deposition method has been used to synthesize diamond films. Thermal diffusivity of these films has be en measured in 120-800 K with a modified Angstrom method. Phonon scatt ering processes are considered to analyze thermal conductivity with th e full Callaway model. In analysis, microstructure of grain boundaries and extended defect concentration give significant effects to the mea n free path of phonons in low temperatures. At high temperatures, the thermal conductivity is governed by the intrinsic thermal resistive pr ocess, the umkalpp process. Thermal conductivity of the films above 50 0 K is shown to close to a recent measurement of natural diamond. This supports that the crystal structure of the films is not different wit h the bulk diamond. (C) 1995 American Institute of Physics.