MEASUREMENTS OF THE THERMAL-CONDUCTIVITY OF CVD DIAMOND FILMS USING MICROMECHANICAL DEVICES

A new technique to measure the thermal conductivity k(T) of CVD diamon d is presented. The thermal conductivity parallel to the surface of fi lms with thicknesses ranging from 2 mu m lip to several hundred mu m c an be determined over a wide temperature range. The measurements are c arried out with micromechanical devices, that are fabricated by standa rd thin film technology. Patterning of the diamond film has been perfo rmed in an oxygen plasma. A thin film heater generates a temperature p rofile which is measured by several thermoresistors. Measured values o f the thermal conductivity of single crystalline silicon show a very g ood agreement with literature results. The thermal conductivities of d iamond films with thicknesses between 3.6 and 8 mu m grown on a silico n substrate by the hot filament technique with different methane conce ntrations have been measured between -195 and 300 degrees C. The measu red values range between less than 1 W/cm K for -195 degrees C and 5 W /cm K for room temperature.