Effect of Operated Pressure on Anticorrosive Behavior of Ta2O5 Thin Film Grown by D.C. Reactive Magnetron Sputtering System

Tantalum oxide (Ta2O5) thin films, 100 nm thick were deposited by D.C. reactive magnetron sputtering system at different operated pressure on unheated p-type silicon (100) wafer and 304 stainless substrates. Their crystalline structure, film surface morphology and optical properties, as well as anticorrosive behavior, were investigated. The structure and morphology of films were characterized by grazing-incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). The optical properties were determined by spectroscopic ellipsometry (SE). The corrosion performances of the films were investigated through potentiostat and immersion tests in 1 M NaCl solutions. The results showed that as-deposited Ta2O5 thin films were amorphous. The refractive index varied from 2.06 to 2.17 (at 550 nm) with increasing operated pressure. The corrosion rate of Ta2O5 thin film improves as the operated pressure decreases. The Ta2O5 thin films deposited at 3 mTorr operated pressure could be exhibited high performance anticorrosive behavior.