Study of cosi2 thermal stability improved by interfacial cavities

The interfacial properties of 70-nm CoSi layers have been modulated by implanting argon or nitrogen after silicide reaction. The effect of the implant has been studied by transmission electron microscopy and sheet resistance analyses. The structural stabilisation of the silicide layer has been attributed to the formation of a band of cavities which have been located at the silicide grain boundaries. They have delayed the occurrence of the grooving process and extended the stability window by 75-100 °C. It has been found that the thermal stability improvement is related to the cavity density and size, and depends on the implanted species. The maximum increment of the thermal budget has been found at a cavity size of 22 nm and a cavity density of 2.5E10 / cm2.