Metal-insulator-metal capacitors using atomic-layer-deposited Al2O3∕HfO2∕Al2O3 sandwiched dielectrics for wireless communications

High density metal-insulator-metal (MIM) capacitors are required for radio frequency and analog/mixed-signal integration circuit applications. In this article, high permittivity Al2O3∕HfO2∕Al2O3 (AHA) dielectrics have been evaluated in comparison with HfO2 using atomic layer deposition technique for MIM capacitor applications. The results indicate that the AHA dielectrics exhibit electrical performance superior to the HfO2 dielectric while retaining similar capacitance density. With respect to 2nm individual Al2O3 barriers, the MIM capacitor can offer a capacitance density of 2.6fF∕μm2, voltage coefficients of capacitance of 71ppm∕V2 and 9ppm∕V, a leakage current as low as 3×10−9A∕cm2 at 1MV∕cm and 125°C, an operating voltage of around 3V for a ten-year lifetime at 125°C in terms of 50% failure.