Thermal Conductivity of Diamond Films Synthesized by Microwave Plasma CVD

A measurement method is developed for the thermal conductivity of thin films in the direction parallel to the surface. Measurements are made between 100°C and 130°C for diannond films from 7 µm to 30 µm thick that are synthesized from a gas phase of methane/hydrogen mixture by microwave plasma chemical vapor deposition, The thermal conductivity of diamond films increases rapidly with decreasing concentration of methane. The highest thermal conductivity ever obtained in this experiment is about 1000 Wm -1 K -1 . The thermal conductivity and Raman spectrum are compared under different synthesis conditions.