Interfacial reactions of Pd/Si0.76Ge0.24 by pulsed KrF laser annealing

The interfacial reactions of ${\mathrm{Pd/Si}}_{\mathrm{0.76}}{\mathrm{Ge}}_{\mathrm{0.24}}$ were studied by pulsed KrF laser annealing as a function of energy density and pulse number. At an energy density of $\text{0.1–0.4\hspace{0.5em}}{\mathrm{J/cm}}^2,$ a continuous germanosilicide layer composed of a low-temperature phase, ${\mathrm{Pd}}_{\mathrm{2}}({\mathrm{Si}}_{\text{1−x}}{\mathrm{Ge}}_x\mathrm{),}$ and a high-temperature phase, $\mathrm{Pd}({\mathrm{Si}}_{\text{1−x}}{\mathrm{Ge}}_x\mathrm{),}$ was formed. In contrast to vacuum annealing, Ge segregation out of the germanosilicide layer and the strain relaxation of the residual ${\mathrm{Si}}_{\mathrm{0.76}}{\mathrm{Ge}}_{\mathrm{0.24}}$ film could be effectively suppressed by pulsed KrF laser annealing at $\text{0.1\hspace{0.5em}}{\mathrm{J/cm}}^2.$ Multiple pulse annealing at 0.1 J/cm² could further homogenize the Pd concentration of the germanosilicide layer and promote the growth of $\mathrm{Pd}({\mathrm{Si}}_{\text{1−x}}{\mathrm{Ge}}_x\mathrm{).}$ Concurrently, the smoothness of the germanosilicide layer was substantially improved in comparison with those grown by vacuum annealing at temperatures above 200 °C. The studies also revealed that for multiple pulse annealing at $\text{0.1\hspace{0.5em}}{\mathrm{J/cm}}^2$ with a low repetition rate, 1 Hz, the evolution of phase formation and Pd diffusion could be proceeded by each individual laser pulse.