Manipulation of the adhesion of copper on carbon is crucial for the production of copper-carbon composites as potential highperformance heat sinks in electronic devices. A thin 100-nm sputter-deposited molybdenum (Mo) interlayer between copper and carbon increases adhesion significantly after thermal treatment. Mo layers of 100 nm have been sputter-deposited on a plane of carbon substrate. SIMS measurements have been performed after rapid heating and subsequent thermal annealing of the samples at the temperatures 400, 500 and 600 • C for 1 min. While the carbon signal measured with SIMS in the Mo interlayer for the sample annealed at 400 • C is very low, a higher-carbon signal at the interface has been detected after annealing at 500 • C. Annealing the sample at 600 • C yields a high-carbon signal throughout the whole Mo interlayer resulting from the formation of Mo 2 C. A cellular automaton model for parallel carbon-Mo layers has been designed in order to simulate the influence of the grain boundaries for the reaction and diffusion process. Comparing the results of the simulation and the experiment, the previously drawn assumption that grain boundary diffusion plays a crucial role for the growth kinetics of Mo 2 C at the Mo-C interface could be corroborated.

Metal-matrix composites are made of materials with different physical and chemical properties. It is possible to change the mechanical, thermal and electrical properties by variation of the mass ratio of the components; therefore, metal-matrix composites have great value for industrial and technological applications. Copper-carbon composites have a good chance to be used as heat sinks for electronic components, which can be explained by their high thermal conductivity, low density and an adjustable coefficient of thermal expansion. On the other hand, the mechanical adhesion of copper and carbon is extremely weak because of their immiscibility and weak chemical interactions. In order to compensate for the low wettability of carbon by copper, a thin molybdenum intermediate layer is used as an adhesion promoter. In this work a time of flight secondary ion mass spectrometry technique was primarily used to detect the carbide formation in the molybdenum and copper layers, depending on different temperature conditions during sputter deposition and annealing afterwards. The CuMo layers were deposited by magnetron sputtering. The adhesion of the samples was determined by a destructive pull-off test. We found that heat treatment mainly modifies the carbide formation in the molybdenum and copper layers.

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