Al₂O₃ Thin Film Deposited By Arc Ion Plating Technique

Alumina oxide is one of the optical thin film material with middle index of refraction. It has high transmissivity in the visible light and near-infared range. Evaporation and magnetron sputter plating are the main physical vapors deposition of alumina oxide film. Ion energy of evaporation is up to 0.1eV, the film is column structure; The ion energy is enhanced to 1～10eV by sputter plating technology and the film structure becomes fine and close. Arc ion plating technique has high ion energy which could achieve 100eV and could be controlled by substrate voltage. Magnetic filtration DC arc ion plating technique without the large particles which is possessed by arc ion plating, could deposit thin film with high surface quality.Alumina oxide thin film on K9 glass was got by magnetic filtration DC arc ion plating and its performance was tested on spectrophotometer, ellipsometer and non-contact surface profile instrument. We studied the influence of technological parameter on the index, extinction coefficient and surface roughness of alumina oxide film, such as O2 component,current of arc ion target and coating time. Moreover deposition rate and uniformity thickness of thin film was studied separately. When current of the arc ion target was 90A, total gas flow rate was 100 seem which include O2 and Argon and O2 was 40 seem, alumina oxide thin film deposited by magnetic filtration DC arc ion plating technique had high transmissivity at visible light and near-infared range. At the wavelength of 550nm, the index of refraction of the thin film was 1.628, extinction coefficient was 1.72×10-3, surface roughness was 0.96nm; the highest deposition rate was up to 24.49nm/min.The results show that:Alumina oxide thin film by this technique has good optical property with high index of refraction and small visible light absorbed. So magnetic filtration DC arc ion plating technique has great potential in the optical thin film preparation technology field.