Thermal conductivity enhancement in Cu/diamond composites with surface-roughened diamonds

Cu/diamond composites have potential as a heat spreading material in small-scale devices. In this study, we show that the use of surface-roughened diamonds obtained by heat treatment under N2 atmosphere and subsequently coated with a thin layer of Ti coating is a feasible method to effectively improve the interfacial bonding and thermal conductivity of Cu/diamond composites. The diamond surface state and prepared composites were investigated by the combination of X-ray diffraction, Raman spectroscopy and microstructure analysis. It is found that the surface-roughened diamonds are in favor of the formation of effective chemical bonds between diamonds and Ti coating through the formation of thin TiC layer and simultaneously provide increased Cu/diamond contact area, which are beneficial to largely decrease the interfacial thermal resistance and thus to greatly enhance the thermal conductivity of Cu/diamond composites.