Measurements of the thermal conductivity of CVD diamond films using micromechanical devices

A new technique to measure the thermal conductivity k(T) of CVD diamond is presented. The thermal conductivity parallel to the surface of films with thicknesses ranging from 2 mu m lip to several hundred mu m can be determined over a wide temperature range. The measurements are carried out with micromechanical devices, that are fabricated by standard thin film technology. Patterning of the diamond film has been performed in an oxygen plasma. A thin film heater generates a temperature profile which is measured by several thermoresistors. Measured values of the thermal conductivity of single crystalline silicon show a very good agreement with literature results. The thermal conductivities of diamond films with thicknesses between 3.6 and 8 mu m grown on a silicon substrate by the hot filament technique with different methane concentrations have been measured between -195 and 300 degrees C. The measured values range between less than 1 W/cm K for -195 degrees C and 5 W/cm K for room temperature.