Effect of the substrate surface condition on the Ni(thin film)/SiC(0001) interfacial reaction
The effect of the substrate surface, structure, and chemistry on the interfacial interaction in Ni(thin film)/SiC was examined, with a focus on the recently discovered formation of a nickel intercalated graphite phase. Very thin Ni films (∼7 nm) were deposited onto heated 6H–SiC(0001) substrates prepared with: (i) an oxide layer, (ii) a surface reconstruction, and (iii) a pristine surface (no oxide and no reconstruction), followed by further annealing. Characterization using x-ray diffraction and atomic force microscopy revealed remarkable differences between the samples in terms of both surface morphology and crystallography. Nickel silicides were present in all samples; however, the phase composition differed depending on sample preparation. Furthermore, the pristine surface was the only one that clearly promoted the growth of the nickel graphite intercalation compound (Ni-GIC).