Formation of cobalt disilicide films on (3×3)6H-SiC(0001)

This paper presents a detailed study of thin Co films grown directly, sequentially, and by codeposition with Si on the (3�3)-R30° surface of 6H-SiC(0001). The structure, chemistry, and morphology of the films were determined using x-ray absorption fine structure, x-ray photoelectron spectroscopy, Auger electron spectroscopy, and atomic force microscopy. For directly deposited Co films (1-8 nm) graphite layers form on top of the film surface during annealing, whereas Co stays mainly unreacted over a temperature range of 300-1000°C. The formation of CoSi₂ is achieved by sequential and codeposition of Co and Si. Films annealed at 550°C are polycrystalline and further annealing to 650°C causes no C segregation, but there is islanding of the films. Attempts to improve film morphology and homogeneity including applying a template method and varying growth temperature are also reported.