Epitaxial CoSi2 formation by Co/Hf bilayers on Si(100)

The epitaxial CoSi/sub 2/ formation on Si(100) by Co/Ti bilayers through solid phase epitaxy is well known. The surface layer consists of TiN or CoTi/sub x/Si/sub y/, depending on the experimental conditions. The role of the barrier layer is to reduce the natural oxide and to limit the flux of the Co atoms into the Si substrate. Several other metals, as Cr, V, Ta and Zr have been used as a barrier layer. We investigated Hf as barrier material in comparison with Ti and Zr barriers. All these materials are able to reduce the natural oxide on silicon.