Influences of Residual Argon Gas and Thermal Annealing on Ta₂O₅ Thin Films

Tantalum pentaoxide (Ta2O5) optical thin films Were deposited on a quartz glass substrate by argon-ion-beam-assisted deposition (IBAD), and the influences of the residual argon gas and thermal annealing processes on the optical properties, stress and compositional and microstructural evolutions of Ta2O5 thin films were investigated in this study. Adopting oxygen thermal annealing treatment-at the temperature of 425 degreesC, the thin films not only reduced the residual argon gas and the, surface roughness, but also provided sufficient stoichiometric ratio. Simultaneously, microstructural examination indicated few nano crystallized structures and voids existed in Ta2O5 thin films, and possessed a reasonable refractive index and a low extinction coefficient. We also suggested the use of IBAD system using a film compositional gas ion beam in replacing the argon ion beam for assisted deposition of optical films.