This letter describes materials and electrical characterization of Pt-Ru binary alloy metal gate electrodes for control of the electrode work function. The work function of the Pt-Ru binary alloy system can be tuned over a wide range of 4.8-5.2 eV. 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 hexagonal close-packed single-phase regions is only weakly dependent on composition, whereas a strong dependence is observed in the intermediate compositional range.