ON THE FORMATION OF COPPER-RICH COPPER SILICIDES

The reaction of copper with silicon in Cu-Si bilayers with overall compositions between copper and the most silicon-rich compound Cu3Si, was monitored by means of several analytical tools, in situ resistance measurements during controlled heating, backscattering, and X-ray diffraction. The order of phase formation was established to be first eta" Cu3Si, followed by the formation of a phase called gamma, with about 17 at.% Si. With a sample of intermediate composition, one then observes the reaction of eta" with gamma, resulting in the formation of the epsilon phase with about 20 at.% Si. The resistivity of the various phases was estimated.