Full ALD Al2O3/ZrO2/SiO2/ZrO2/Al2O3 Stacks for High-Performance MIM Capacitors

Metal-insulator-metal (MIM) capacitors with full atomic-layer-deposition Al₂O₃/ZrO₂/SiO₂/ZrO₂/Al₂O₃ stacks were explored for the first time. As the incorporated SiO₂ film thickness increased from 0 to 3 nm, the quadratic and linear voltage coefficients of capacitance (α and β) of the MIM capacitors reduced significantly from positive values to negative ones. For the stack with 3-nm SiO₂ film, a capacitance density of 7.40 fF/μm², α of -121 ppm/V², and β of -116 ppm/V were achieved, together with very low leakage current densities of 3.08 × 10^-8 A/cm² at 5 V at room temperature (RT) and 5.89 × 10^-8 A/cm² at 3.3 V at 125 °C, high breakdown field of 6.05 MV/cm, and high operating voltage of 6.3 V for a 10-year lifetime at RT. Thus, this type of stacks is a very promising candidate for next generation radio frequency and analog/mixed-signal integrated circuits.