Simulation and dielectric characterization of reactive dc magnetron cosputtered (Ta2O5)1−x(TiO2)x thin films

Abstract

New capacitor material with high dielectric constant is needed for future integrated capacitor structures. Tantalum pentoxide (Ta2O5) is considered as one of the most promising candidates. In this article, thin films of (Ta2O5)1−x(TiO2)x were grown utilizing reactive dc magnetron cosputtering of tantalum and titanium in an argon/oxygen atmosphere. By varying the input power at the targets, the composition of the thin film is easily controlled. The composition of the films was analyzed with elastic recoil detection analysis revealing the titanium oxide content (x ranging from 0 to 0.40). The presented results indicate that reactive sputter deposited tantalum pentoxide, with or without the addition of titanium, exhibits the properties required to meet the demands for future dielectric materials in integrated capacitors. The dielectric constant for metal-insulator-semiconductor structures is about 20 and the leakage current density is below 10 nA/cm2 at 0.5 MV/cm, if the annealing temperature does not exceed 600 °C. Annealing at 800 °C leads to ∼50% increase in dielectric constant with a cost of a severe increase in leakage current.