Heatsinks and heat spreaders should dissipate the heat caused by the power loss of electronic components and release it to the ambient fluid. Due to the fact that electronic systems are often thermally cycled, the selection of materials used for packaging is very important. The reliability of the device depends strongly on the compatibility of the chosen materials. The coefficient of thermal expansion (CTE) is the essential material parameter. The better the matching of the CTE the less mechanical stress is induced. The low CTE of silicon or gallium arsenide are especially known to cause problems.
Metal graphite composites offer a solution to this problem. These materials combine a high thermal conductivity with a low CTE. Complex geometrical structures can be realized and the whole device can be metalized to connect it to the circuit by soldering.