Contactless measurement of the thermal conductivity of thin SiC layers

We demonstrate a contactless measurement of the thermal conductivity of free standing silicon carbide (SiC) thin films. A laser is used to heat the thin film locally and at the same time to detect the Raman signal. The temperature as determined from the intensity ratio of Stokes and anti-Stokes Raman lines is used to calculate the thermal conductivity. For a SIC sample grown at low temperature by CVD we measure a thermal conductivity which is lower, by a factor of 20 compared to values reported for bulk crystalline SiC, a fact that ive ascribe to the polycrystalline morphology of our sample. The LO and TO phonon lines are considerably broadened compared to single crystal SiC. We discuss the influence of stacking faults on the linewidths.