In a semiconductor device, a relatively deep germanium implant and activation thereof precedes deposition of the nickel for nickel silicide formation. The activation of the germanium causes the lattice constant in the region of the implant to be increased over the lattice constant of the background substrate, which is preferably silicon. The effect is that the lattice so altered avoids formation of nickel disilicide. The result is that the nickel silicide spiking is avoided.