The interfacial reaction of Ni with (111)Ge, (100)Si_0.75Ge _0.25 and (100)Si at 400 °C

The reaction of Ni with Ge, Si_0.75Ge_0.25 and Si using rapid thermal annealing (RTA) and in-situ annealing method at 400 °C produces different phases, as revealed by cross-sectional transmission electron microscopy (TEM). A uniform film of nickel germanide (NiGe) was formed at 400 °C for the Ni reaction with Ge using the in-situ annealing technique, whereas Ni₃Ge₂ and NiGe phases were found using the RTA method. For the reaction between Ni and Si, a highly textured NiSi film was obtained at 400 °C for RTA whereas Ni₃Si₂ and NiSi were found using the in-situ annealing method. On the other hand, a relatively uniform NiSiGe was formed using RTA; Ni₃(Si_1-yGe _y)₂ and Ni(Si_1-xGe_x) (x<y<0.25) were observed for the in-situ annealing. Different annealing time is identified as the mechanism responsible for the formation of the various phases.