Hydrogen-Robust Submicron IrOx/Pb(Zr, Ti)O3/Ir Capacitors for Embedded Ferroelectric Memory

We have demonstrated that the scaling of IrOx(Pb(Zr, Ti)O3:PZT)/Ir capacitors can be extended into the submicron regime. The submicron IrOx/PZT/Ir capacitors were fabricated using a one-mask stack-etch process, integrated with an SiO2 interlayer dielectric, and contacted with Al metallization. The aggregate electrical properties of integrated PZT capacitor arrays are shown to be nearly independent of individual capacitor area in the range between 102 µm2 and 0.12 µm2. In particular, switched polarization values of more than 30 µC/cm2 were obtained for PZT capacitors with an individual capacitor area of 0.12 µm2. This result suggests that the lateral scaling can be achieved down to 0.1 µm2. Through the use of appropriate diffusion barriers, hydrogen-robust submicron PZT capacitors are obtained. No degradation in ferroelectric properties of submicron PZT capacitors was observed under the test conditions. These results suggest that PZT capacitors can be integrated into a standard complementary metal oxide semiconductor (CMOS) process flow with minimal degradation.