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/£m², quadratic voltage coefficients of capacitance of 436 ppm/V², and a leakage current as low as 2.3×10⁻⁸ A/cm² at 1 MV/cm.