Electrical characteristics of ALD SiO2-HfO2-SiO2 MIM capacitors with low quadratic voltage coefficients of capacitance

High densities with low voltage coefficients of capacitances (VCCs) of Metal-insulator-metal (MIM) capacitors are required for the application of radio frequency and analog/mixed-signal integrated circuits. In this paper, the MIM capacitors with SiO2-HfO2-SiO2 (SHS) sandwiched dielectrics structures are fabricated. The results indicate that with the proper combination, the SHS dielectrics exhibit high capacitance while remaining relatively low VCCs. For the 1.5 nm individual SiO2 layers, the MIM capacitor can offer a capacitance density of 9 fF/mu m(2), quadratic voltage coefficients of capacitance of 436 ppm/V-2, and a leakage current as low as 2.3 x 10(-8) A/cm(2) at 1 MV/cm.