Research On The Optical Properties Of Dielectric Single-layers And Surface Defects Of Multi-layers

Dielectric materials are comprehensively applied in optics and electrics, especially for tantalum oxides (Ta₂O₅). As one of the most important dielectric materials, Ta₂O₅ thin films are widely used in thin film flat displays, cameras, optical communication devices, analytical instruments and so on. In this thesis, we maily focused on the optical properties of Ta₂O₅ single layers and the microdefects of infared cut off filter (IR for short) which prepared by taking TiO₂ and SiO₂ as high and low refractive index materials.The optimized deposition parameters have been obtained by orthogonal experiments, which reveal that the best optical properties will be achieved in the near-ultraviolet wavelength region under the condition: substrate temperature 250℃, deposition rate5(?)/s, oxygen flow 14sccm; while in the near-infared wavelength region: substrate no baked, deposition rate 5(?)/s (or 7 (?)/s), oxygen flow 18sccm.The influence of substrate temperature and film thickness no the optical and structure properties of Ta₂O₅ thin films has been investigated by spectrophotometer and atomic force microscopy (AFM). Results show that: the refractive index increases with the increasing of substrate temperature but seems to be immune to the film thickness. The surface roughnesses become lower and lower with the increasing of substrate temperature and film thickness, which is mainly caused by the different film grow models under different substrate temperatures. X-ray photoelectron scan (XPS) result reveals that the chemical compositions of tantalum oxide thin film prepared under the condition: substrate temperature250℃, deposition rate5(?)/s, oxygen flow 14sccm are mainly composed of Ta₂O₅,TaOx (12O₅ optical thin films. The results of microdefects of multilayers are meaningful for further researches.