Microstructure and dielectric properties of amorphous BaSm2Ti4O12 thin films for MIM capacitor

BaSm2Ti4O12 (BST) film grown at room temperature was amorphous, while the film grown at 300 degrees C was also amorphous but contained a small amount of crystalline Sm12Ti2O7 (ST). The crystalline BST phase was formed when the film was grown at 700 degrees C and subjected to rapid thermal annealing (RTA) at 900 degrees C. On the other hand, the ST phase was formed in the film grown at 300 degrees C and subjected to RTA at 900 degrees C. A high capacitance density of 2.12 fF/mu m(2) and a low leakage current density of 1.15 fA/pF V were obtained from the 150 nm-thick BST film grown at 300 degrees C. Its capacitance density could conceivably be further increased by decreasing the thickness of the film. It had linear and quadratic coefficients of capacitance of -785 ppm/V and 5.8 ppm/V-2 at 100 kHz, respectively. Its temperature coefficient of capacitance was also low, being approximately 255 ppm/degrees C at 100 kHz. (C) 2006 Elsevier Ltd. All rights reserved.