Raman study on the Ni/SiC interface reaction

Ni/SiC interface reaction was investigated by Raman scattering. The specimen consisted of a 200 nm Ni layer deposited on a both-side polished 6H-SiC wafer with postannealing at 500-1100 degreesC. Raman spectra were observed from both faces of the specimen, i.e., from the Ni layer side and from the opposite (SiC wafer) side. The spectra showed that nickel silicides were formed by annealing at above 500 degreesC, and diffusion of Si atoms into the Ni layer played a key role in forming an ohmic contact at above similar to900 degreesC. It was also found that carbon atoms that did not react with Ni formed nanometer-size clusters. This work clearly demonstrates that Raman scattering is useful for studying interface reactions between metallic electrodes and SiC. (C) 2002 American Institute of Physics.