Structural and Electrical Properties of Mn-Doped Thin Film Grown on Substrate for RF MIM Capacitors

Mn-doped Bi₄Ti₃O₁₂ (M-B₄T₃) films were well formed on a TiN/SiO₂/Si substrate at 200degC without buckling using RF magnetron sputtering. The leakage current density of these films was considerably influenced by the oxygen partial pressure (OPP), which was attributed to the presence of oxygen vacancies or oxygen interstitial ions. The film grown under 2.8-mtorr OPP showed the lowest leakage current density. The M-B₄T₃ films grown at 200degC showed a high dielectric constant of 38 with a low loss in both kilohertz and gigahertz ranges. The 39-nm-thick film showed a high capacitance density of 8.47 fF/mum² at 100 kHz, and its temperature and quadratic voltage coefficients of capacitance were low at approximately 370 ppm/degC and 667 ppm/V², respectively, with a low leakage current density of 7.8 times 10^-8 A/cm² at 2 V. Therefore, the M-B₄T₃ thin film grown on a TiN/SiO₂/Si substrate is a good candidate material for high performance, radio frequency metal-insulator-metal capacitors.