Structural and electrical properties of Ni-germanosilicides formed using pulsed KrF laser annealing

We have fabricated the Ni-germanosilicide using Ni deposition on relaxed Si_1-xGe_x layers (x =0.15, 0.25), followed by the pulsed KrF laser annealing with the energy densities of 600 and 800 mJ/cm², and investigated their electrical and structural properties. Regardless of Ge contents in Si_1-xGe_x layer, the Ni(Si_1-xGe_x)₂ film was epitaxially grown on underlying layers after laser annealing. For an energy density of 600 mJ/cm², the thickness of Ni(Si_1-xGe_x)₂ on the Si_0.75Ge_0.25 layer was relatively thicker than that on Si_0.85Ge_0.15 one. This could be attributed to the decrease in the melting temperature of Si_1-xGe_x alloys with an increase in Ge content. In other word, an increase in Ge content in Si_1-xGe_x layer led to the increase in melting depth of Si_1-xGe_x layer, allowing the formation of thicker Ni(Si_1-xGe_x)₂ film caused by excimer laser induced liquid-phase mixing of Ni film into the molten Si_1-xGe_x layer. The sheet resistance degradation of Ni(Si_1-xGe_x)₂ film formed on Si_0.75Ge_0.25 layer after laser annealing with the energy density 800 mJ/cm² could be attributed to nonuniform interface between Ni(Si_1-xGe_x)₂ and Si_0.75Ge_0.25 layers caused by higher threading dislocation densities in Si_0.75Ge_0.25 layer.