THE MEASUREMENT OF THERMAL-PROPERTIES OF DIAMOND

Steady state and laser-flash methods were developed for measuring the thermal conductivity of various types of diamond films; single crystal by homoepitaxial growth, single crystal synthesized by a high-pressur e and high-temperature (HP/HT) method and polycrystalline film grown b y chemical vapor deposition(CVD). The dependence of thermal conductivi ty on impurity, crystallinity and grain size was studied. Single cryst als obtained. by homoepitaxial growth showed isotropic thermal conduct ivity, while polycrystalline films grown by microwave plasma assisted CVD showed anisotropic thermal conductivity. The concentration of nitr ogen was observed to affect the thermal conductivity of type Ib single crystal diamond synthesized by the HP/HT method. In the case of polyc rystalline diamond, thermal conductivity was found to depend on crysta llinity and grain size. (C) 1997 Elsevier Science S.A.