Mixed high dielectric constant layers for MOS devices

Abstract

Abstract Tantalum oxide-Ta2O5 mixed zirconium oxide-ZrO2 (TZO) films were deposited on p-silicon substrates using RF magnetron co-sputtering technique. The presence of tantalum, zirconium and oxygen atoms was confirmed by Rutherford Back Scattering analysis with NDF program. XRD spectra revealed that the as-deposited and annealed TZO films were amorphous in nature. It is observed that the accumulation region has become stable after annealing and also observed the reduction in the intensity of the kinks/bumps at depletion region of the C-V curves. The dielectric constant value is also reasonably in good agreement with the reported values at this annealing temperature. The J-V curves revealed that the annealing process effectively reduced the leakage current density upto nano scale range at this lower annealing temperature. The mixed TZO layer showed relatively better thermodynamic and electrical properties after annealing at even lower temperature.