Effect of Postdeposition Annealing on the Structural, Electrical, and Optical Properties of DC Magnetron SputteredTa2O5Films

[摘要] Thin films of tantalum oxide were formed on quartz and silicon (111) substrates kept at room temperature (303 K) by reactive sputtering of tantalum target in the presence of mixture ofoxygen and argon gases. The as-deposited films were annealed in air for an hour in thetemperature range 673–873 K. The films were characterized by studying structural, dielectric,electrical, and optical properties. The as-deposited films were amorphous in nature. As theannealing temperature increased to 673 K, the films were transformed into polycrystalline.Electrical characteristics of as-deposited and annealedTa2O5thin films were compared. Thethermal annealing reduced the leakage current density and increased the dielectric constant. Theoptical transmittance of the films increased with the increase of annealing temperature. The as-depositedfilms showed the optical band gap of 4.38 eV. It increased to 4.44 eV with the increaseof annealing temperature to 873 K. The as-deposited films showed the low value (1.89) ofrefractive index and it increased to 2.15 when annealed at 873 K. The increase of refractive indexwith annealing temperature was due to the increase in the packing density and crystallinity of thefilms.

[学科分类] 材料工程