Interfacial reactions of Ni on Si1−xGex (x=0.2, 0.3) at low temperature by rapid thermal annealing

The interfacial reaction of Ni with relaxed ${\mathrm{Si}}_{\text{1−x}}{\mathrm{Ge}}_x$ $\text{(x=0.2,0.3)}$ films in the low temperature range, viz., 300–500 °C, has been investigated and compared with that of Ni with Si (i.e., $\text{x=0).}$ ${\mathrm{Ni}}_2({\mathrm{Si}}_{\text{1−x}}{\mathrm{Ge}}_x)$ and ${\mathrm{Ni}}_3({\mathrm{Si}}_{\text{1−x}}{\mathrm{Ge}}_x{)}_2$ were observed at 300 °C whereas a uniform film of ${\mathrm{Ni(Si}}_{\text{1−x}}{\mathrm{Ge}}_x)$ was formed at 400 °C for both ${\mathrm{Si}}_{\text{0.8}}{\mathrm{Ge}}_{\text{0.2}}$ and ${\mathrm{Si}}_{\text{0.7}}{\mathrm{Ge}}_{\text{0.3}}$ substrates. At 500 °C, a mixed layer consisting of $\mathrm{Ni}({\mathrm{Si}}_{\text{1−y}}{\mathrm{Ge}}_y)$ and ${\mathrm{Si}}_{\text{1−z}}{\mathrm{Ge}}_z$ was formed with a relation of $\mathrm{z>x>y.}$ Sheet resistance measurement results show that the silicided film attains its lowest value at an annealing temperature of 400 °C. The approximate values of the resistivity of the corresponding uniform $\mathrm{Ni}({\mathrm{Si}}_{\text{1−x}}{\mathrm{Ge}}_x)$ $\text{(x=0.2,\hspace{0.17em}0.3)}$ derived from the transmission electron microscope and sheet resistance results are 19 and 23 μΩ cm, respectively.