Properties of Amorphous and Crystalline Ta2O5 Thin Films Prepared by Metalorganic Solution Deposition Technique for Integrated Electronic Devices

Abstract

AbstractWe report on the properties of Ta2O5 thin films prepared by the metalorganic solution deposition (MOSD) technique on Pt-coated Si, n+-Si, and poly-Si substrates. The effects of postdeposition annealing temperature on the structural, electrical, and optical properties were analyzed. The electrical measurements were conducted on MIM and MIS capacitors. The dielectric constant of amorphous Ta2O5 thin films was in the range 29.2-29.5 up to 600°C, while crystalline thin films, annealed in the temperature range 650–750°C, exhibited enhanced dielectric constant in the range 45.6–51.7. The dielectric loss factor did not show any appreciable dependence on the annealing temperature and was in the range 0.006–0.009. The films exhibited high resistivities of the order of 1012–1015 Δ-cm at an applied electric field of 1 MV/cm in the annealing temperature range of 500-750 °C. The temperature coefficient of capacitance was in the range 52-114 ppm/°C for films annealed in the temperature range 500-750°C. The bias stability of capacitance, measured at an applied electric field of 1 MV/cm, was better than 1.41 % for Ta2O5 films annealed up to 750°C.