Electrical properties of epitaxial NiSi2/Si contacts with extremely flat interface formed in Ni/Ti/Si(0 0 1) system

We have investigated the morphology and the electrical properties of epitaxial NiSi2/Si contacts formed in a Ni/Ti/Si(0 0 1) system. An atomically flat interface between an epitaxial NiSi2 layer and a Si(0 0 1) substrate without {1 1 1} facets can be formed by annealing at 750 °C. Glazing angle X-ray reflectivity measurements reveal that interface is extremely flat and uniform over areas as wide as about 1 mm2. Local and inhomogeneous formation of Ni4Ti4Si7 and C54–TiSi2 grains are observed in the NiSi2 layer and on the surface, respectively, after annealing at 850 °C. The epitaxial NiSi2 layer exhibits high thermal robustness compared to a NiSi layer formed in a conventional Ni/Si system and the sheet resistance of the epitaxial NiSi2 layer formed in Ni/Ti/Si systems keeps the low value in the annealing at the temperature ranging between 650 °C and 850 °C. Schottky barrier heights of this epitaxial NiSi2/Si contacts for n- and p-type are estimated to be 0.30 and 0.37 eV, respectively.