Fully logic compatible (1.6V Vcc, 2 additional FRAM masks) highly reliable sub 10F2 embedded FRAM with advanced direct via technology and robust 100 nm thick MOCVD PZT technology

We newly developed a highly reliable 100 nm thick MOCVD PZT technology and a novel direct cell via technology applicable to fully logic compatible sub 10F² cell embedded FRAM. A 2Pr value of 40 uC/cm² at 1.6V was obtained on our one-mask etched new PTO seeded 100 nm thick MOCVD PZT capacitor. Capacitor degradation that could occur upon a direct application of metal on capacitor through direct via was completely prevented by combining a novel TiN-plug scheme and a diffusion barrier metal technology, which greatly improves the interface properties between top electrode and PZT. Finally, a highly reliable, 1.6V operational, sub 10F² cell FRAM has been successfully embedded into experimental 0.18 μm logic with only two additional FRAM masks by successfully implementing the above two key technologies.