Preparation And Anealing Effect On Optical Performance Of Ta₂O₅ Thin Film

Optical thin film is a kind of nano-material which many researchers and users pay much attention to. It has been widely used in indicator, solar battery, optical communication and laser device industries etc. The preparation process , dielectric property and optical property of Ta-2O₅ thin film been deeply researched by investigators .The preparation parameters, post treatment and growth mode exerts strong influence on microstructure and property of the thin film. The growth mode would be destroyed and become more complicated when the ion beam was introduced into the grow process of thermal evaporation deposition.We prepared Ta₂O₅ thin films by electron-beam deposition system with and without ion source assisted and studied influence of preparation parameters exerts on properties of Ta₂O₅ thin film. We analyzed the raw material and Ta₂O₅ thin films with XRD and XPS. The result shows that the premelting material is mainly Ta₂O₅ and Ta₂O₅ is steady under the process of electron-beam deposition. The Ta₂O₅ thin films we prepared are amorphous and the ratio of O to Ta are 2.69. We measured the transmittances spectra through UV 755B and U-4100 Spectrophotometer, and deduced refractive indexes from the extremums of transmittances. The optical performance of thin films were investigated at various process parameters, such as base vacuum and ion source. The result shows that higher base vacuum or ion source both can improve the refractive indexes of Ta₂O₅ thin films . We got informations about surface topography, roughness and phase error of the thin films which prepared with ion source assisted by AFM. The result shows that the Ta₂O₅ thin film has excellent roughness and the roughness enlarged with the thickness accretion of Ta₂O₅ thin film. The film grows in island mode with ion source assisted.We also researched the property of Ta₂O₅ thin films were annealed under different atmosphere. The films prepared by electronic beam deposition with and without ion beam assisted were both chosen for anneal. The process parameters we chosen include anneal in air and in Ar, annealing temperature(300℃,400℃,500℃,600℃) and holding time(2h,3h,4h). The experiments result shows that Ta₂O₅ thin films be annealed under 600℃are amorphous. Anneal has different influence on films' refractive indexes, transmittance and the drift of transmittance extremum. TheTa₂O₅ thin film prepared by electronic beam deposition without ion beam assisted has higher steadied than those Ta₂O₅ thin films prepared by electronic beam deposition with ion beam assisted.