Ni–Al diffusion barrier layer for integrating ferroelectric capacitors on Si

Abstract

We report on the use of amorphous Ni–Al film (a-Ni–Al) as conductive diffusion barrier layer to integrate La₀.₅Sr₀.₅CoO₃/PbZr₀.₄Ti₀.₆O₃/La₀.₅Sr₀.₅CoO₃capacitors on silicon. Cross-sectional observation by transmission electron microscope reveals clean and sharp interfaces without any discernible interdiffusion/reaction in the sample. The physical properties of the capacitors are vertically characterized as the parameters of memory elements. Excellent ferroelectric properties, e.g., large remnant polarization of ∼ 22 μC/cm², small coercive voltage of ∼ 1.15 V, being fatigue-free, good retention characteristic, imply that amorphous Ni–Al is an ideal candidate for diffusion barrier for the high-density ferroelectric random access memories integrated with silicon transistor technology.