New metal-insulator-metal capacitor based on SrTiO3/Al2O3/SrTiO3 laminate dielectric

A novel high-performance metal-insulator-metal (MIM) capacitor for analog and radio-frequency (RF) applications has been developed using SrTiO₃/Al₂O₃/SrTiO₃ laminate as the dielectric. A very high capacitance density of 19.13 fF/μm² has been achieved due to the perovskite SrTiO₃ (STO) with a very high dielectric constant of 145. This MIM capacitor also displays a quadratic voltage coefficient of 610 ppm/V² and a good leakage current of 5 × 10^-9 A/cm² at 2 V, which is attributed to the inserted Al₂O₃. Since experiments demonstrated that Schottky emission is the dominant conduction mechanism, further reduced leakage characteristic and quadratic voltage coefficient could be achieved by using high work-function (Φ_m) materials as the electrodes to increase the band offset. The combination of the promising electrical properties and the compatible process integration in standard CMOS technologies reveal this structure highly appropriate for advanced MIM capacitors.