Schottky Barrier Characteristics of Cobalt–Nickel Silicide/n-Si Junctions for Scaled-Si CMOS Applications

Ternary cobalt–nickel silicide/n-Si Schottky diodes have been fabricated by sputtering using an equiatomic cobalt–nickel alloy target. A minimum sheet resistivity of the ternary silicide is found to be 5–7Ω / sq. Grazing-incidence X-ray diffraction shows the formation of ternary silicide phases. Cross-sectional TEM micrograph shows a fairly uniform diffusion of metals into Si with the formation of fully silicided film. Selected-area electron diffraction pattern exhibits the crystalline nature of the silicide layer. Temperature-dependent electrical current–voltage measurements have been used to characterize an optimized Schottky diode formed by annealing at 450∘C. The room-temperature barrier height and ideality factor are found to be 0.656 eV and 1.6, respectively, from theI–Vcharacteristics. The series resistance of the diode has been calculated and is found to be 1–11.8kΩ. The variation of barrier height has been attributed to the inhomogeneity in Schottky junction.