High performance metal-insulator-metal capacitor using a SrTiO3/ZrO2 bilayer

Future integration of metal-insulator-metal capacitors requires devices with high capacitance density and low quadratic voltage coefficient of capacitance (α). A major problem is that the increase in capacitance density is usually accompanied by increased voltage nonlinearities. By combining two high-k materials with opposite α, it is demonstrated that it is possible to obtain capacitors with both high capacitance density and minimal nonlinearity. A SrTiO3/ZrO2 bilayer was used to elaborate capacitors displaying a voltage coefficient of −60 ppm/V2 associated with a density of 11.5 fF/μm2. These devices constitute excellent candidates for the next generation of metal-insulator-metal capacitors.