MIM capacitors using BaSm₂Ti₄O₁₂ and Sm₂Ti₂O₇ dielectrics

The dielectric properties of BaSm2 Ti4 O12 (BST) and Sm2 Ti2 O7 (ST) films were investigated in order to evaluate their potential for use in metal-insulator-metal (MIM) capacitors. The crystalline BST phase was formed when the film was grown at 700°C and subjected to rapid thermal annealing (RTA) at 900°C. The ST phase was formed in the film grown at 300°C and subjected to RTA at 900°C. A high capacitance density of 4.84 fFμ m2 and a low leakage current density of 4.28 fApF V were obtained from the BST film with a thickness of 138 nm. The BST film has the linear and quadratic coefficients of capacitance of 684 ppmV and -295 ppm V2, respectively, and a temperature coefficient of capacitance of -136 ppm°C at 100 kHz. The ST film has a high capacitance density (3.47 fFμ m2) and a very low leakage current density (0.26 fApF V). The ST film also showed small voltage and temperature coefficients of capacitance. Therefore, both the BST and ST films are good candidate materials for MIM capacitors.