Experimental considerations of CVD diamond film measurements using time domain thermoreflectance

Diamond has the highest known thermal conductivity of any known bulk material, but the properties of synthetic diamond films often fall far short of this high level. The DARPA program Thermal Transport in Diamond Films for Electronics Thermal Management brings together researchers from five universities to comprehensively characterize the thermal transport and material properties of CVD diamond thin films in an effort to better how to further improve the thermal transport properties and understand how accurately these properties can be measured using time domain thermoreflectance and Raman spectroscopy. Here we summarize the results of the thermal measurements of diamond conducted via time domain thermoreflectance (TDTR) using two different systems and discuss some difficulties of accurately measuring the thermal conductivity of micron-thick anisotropic films that often have high surface roughness. We also report that in certain cases the thermal conductivity and thermal boundary conductance of CVD diamond films has been improved to the point of making them highly attractive for thermal management of high power electronic devices.