TOFSIMS elemental mapping was applied to characterize SiC reinforced copper. SiC grain in Cu, compressed by hot isostatic pressing, is an innovative substrate material for improved heat dissipation of high-power semiconductor devices so that traditional substrates like Cu, Al, Al2O3 and metal alloys could be complemented. The TOFSIMS imaging capabilities combined with its excellent detection limits were used to monitor the matrix components as well as the distribution of an alloying additive (Ti) which is necessary to improve the mechanical strength. It turned out that SiC-Ti interface reactions lead to a dissipation of Si into the Cu matrix which deteriorates heat conduction. The TOFSIMS analyses helped to gain a better understanding of the complex Cu/SiC composite system which in turn gives room for further process improvements. (c) 2006 Elsevier B.V. All rights reserved.