Mesotaxy: Formation of buried single-crystal CoSi sub 2 layers by implantation.

Using high dose implantation of 200 KeV Co ions followed by high temperature annealing, we have created buried layers of CoSi sub 2 in crystalline Si of both (100) and (111) orientations. For a dose of 3x10 sup (17) Co/cm sup 2, the layer that forms is ~1100angstroms thick and the overlying Si is ~600angstroms thick. A lower dose of 2x10 sup (17) Co/cm sup 2 yields a thinner layer, 700angstroms thick, under 1200angstroms of crystalline Si. Rutherford Backscattering and channeling analysis of the layers shows that they are aligned with the substrate (X sub (min) of the Co as low as 6.4%) and TEM inspection of the (100) Co Si sub 2 /Si interfaces shows that they are abrupt and epitaxial (with occasional small facets). Moreover, electrical characterization of these layers yields resistance ratios that are better than epitaxial CoSi sub 2 films grown by more conventional UHV methods.