Temperature dependence of Ni-germanide formed by Ni-Ge solid-state reaction

The solid-state reaction of nickel and substrate germanium was performed by isochronously annealing at a temperature ranging from 250-600/spl deg/C in vacuum. The reaction has been begun at 250/spl deg/C, and substantial polycrystalline NiGe film has been formed at 350/spl deg/C. The formed NiGe film has an orthorhombic structure with dimensions comparable to that of bulk NiGe. With increasing the annealing temperature from 400 to 600/spl deg/C, the film surface roughness increases due to the increase of the grain size. All nickel germanide/n-Ge Schottky contacts has similar Schottky barrier height around 0.47-0.48 eV due to the Fermi level pinning effect.