Medium-energy ion-scattering study of a possible relation between the Schottky-barrier height and the defect density atNiSi2/Si(111) interfaces

We have studied the electrical properties of both orientations of the ${\mathrm{NiSi}}_2$/Si(111) interface in relation to the atomic structure at the very interface. The flat-band Schottky-barrier heights corresponding to the A- and B-type oriented silicides are shown to be 0.65 and 0.81 eV, respectively, in agreement with the literature. Measurements using medium-energy ion scattering show that the concentrations of atoms displaced from lattice sites at the A- and B-type oriented ${\mathrm{NiSi}}_2$/Si(111) interfaces are smaller than ∼1×${10}^{13}$ Si atoms ${\mathrm{cm}}^{\mathrm{-}2}$ and ∼3×${10}^{13}$ Si atoms ${\mathrm{cm}}^{\mathrm{-}2}$, respectively, ruling out the possibility that the difference in Schottky-barrier height is caused by defects. The difference should therefore be intrinsically related to the interfacial atomic geometry.