Ion-beam induced mixing of Cu/Au bilayer thin film (kinematics and formation of solid solutions)

Ion-beam induced atomic mixing of Cu/Au bilayer thin film is studied using combined electrical resistivity measurements and Rutherford Backscattering Spectrometry (RBS). 400 keV Kr⁺ ion irradiation with fluences ranging from 3.3×10¹⁵ to 7.6×10¹⁶ ions/cm² at room temperature have been used. Ion beam mixing lead to a uniformly mixed metal alloy. The formation of Cu/Au solid solutions depends on the initial composition and on the fluence of irradiating ions. For an initial composition of Cu₄₂Au₅₈, a Cu-rich solid solution of composition Cu₇₂Au₂₈ is formed after irradiation with 7.6×10¹⁶ ions/cm². The kinematics of the intermixing process is also studied by in situ electrical resistivity measurements which confirmed the formation of the Cu/Au solid solutions.