BaTi ₄O ₉ thin films for high-performance metal-insulator-metal capacitors

The dielectric and electrical properties of a BaTi4 O9 film were investigated in order to evaluate its potential use in metal-insulator-metal (MIM) capacitors for rf/mixed signal integrated circuits. A high capacitance density of 4.62 fFμ m2 along with a low tan δ of 0.0025 were obtained at 100 kHz. A high capacitance density of 4.12 fFμ m2 and a high quality factor of 322 were also achieved at 2 GHz. The leakage current density was approximately 1 nA cm2 at ±2 V. Small linear and quadratic voltage coefficients of capacitance of 110 ppmV and 40.05 ppm V2, respectively, and a small temperature coefficient of capacitance of -92.157 ppm°C at 100 kHz were obtained. These results demonstrate that the BaTi4 O9 film is a good candidate material for MIM capacitors.