Comparison of the Work Function of Pt–Ru Binary Metal Alloys Extracted From MOS Capacitor and Schottky-Barrier-Diode Measurements

This paper describes a systematic comparison of work function for the Pt-Ru binary-alloy metals, extracted from capacitance-voltage (C-V) characteristics of MOS capacitors and the current-voltage (I-V) and C-V characteristics of Schottky-barrier diodes. Our results indicate that the work function of the Pt-Ru binary-alloy system can be tuned over the wide range of 4.8-5.2 eV. Furthermore, the results indicate that the change of film properties, i.e., resistivity, work function, and crystal structure, with composition is consistent with the equilibrium-phase diagram and that the work function in the face-centered cubic and the hexagonal-close-pack single-phase regions is only weakly dependent on composition while a strong dependence is observed in the intermediate compositional range. It is also observed that work-function values obtained from the Schottky I-V analysis are significantly lower than those extracted from the MOS C-V data