High Performance Metal-Insulator-Metal Capacitors with Er2O3 on ALD SiO2 for RF Applications

Abstract

MIM capacitors for RF applications with sputtered Er2O3 on ALD SiO2 stacked dielectrics with excellent capacitance performance were demonstrated for the first time. An MIM capacitor with 8.8 nm Er2O3 on 3 nm SiO2 stacked dielectrics displayed a high capacitance density of 7 fF/μm2, a low quadratic VCC of less than 100 ppm/V2, a low leakage current at 3.3 V bias of 1 × 10−8 A/cm2, and a high dielectric field strength of 8.7 MV/cm. Having leakage currents of 1 × 10−7 and 4 × 10−8 A/cm2 at 3.3 and 2 V, respectively, the MIM capacitor with 7 nm Er2O3 on 3 nm SiO2 stacked dielectrics demonstrated a capacitance density of 7.4 fF/μm2 and quadratic VCCs of −91 and −255 ppm/V2 at 10 and 100 kHz, respectively. The low quadratic VCC α was obtained by compensating the positive α of Er2O3 with the negative α of SiO2, while the low leakage current and high oxide field strength demonstrated were due to the high quality SiO2 deposited by the ALD method.