Control of Ni/SiC reactions by germanium, studied on the atomic scale

Atomic-scale processes between Ni and 6H–SiC, mediated by a Ge interlayer, are reported; these processes are relevant for microelectronics and composite design. In particular, the structure and the phase composition in these Ni/Ge/6H–SiC specimens were studied by high-resolution transmission electron microscopy, high-angle annular dark field imaging, and energy dispersive X-ray spectroscopy. On the 6H–SiC surface ε-Ni5−δGe3 was formed, which interacted with the 6H–SiC, resulting in a solid solution between nickel silicide and nickel germanide with dissolved carbon. Subsequently, the carbon segregated graphitically.