Evaporation

the classical method of thin film deposition

is still commonly used for the production of optical coatings today. The technique of electron beam evaporation delivers a high rate of deposition. Three dimensional or curved substrates are also coated by e-beam evaporation in order to achieve good film thickness distribution. Because of the low energy of the condensing particles the packing density of thermally evaporated films is very low. The achieved film properties are quite different to those of the respective bulk materials. The typical columnar microstructure of many metals and oxides has been investigated by various workers. The low packing density implies that the optical constants and mechanical properties are inferior to those of the bulk materials. Deposition processes using higher particle energies can improve the film properties. With ion assisted deposition

a growing thermally evaporated film is bombarded with an energetic ion beam. Due to the momentum transfer from the incoming ions to the condensing molecules

the mobility of the particles is increased significantly. This results in higher packing densities and improved mechanical properties. A wide range of materials and completed layer systems have been investigated by many laboratories. The limited ion current and beam size of the available ion sources reduces the useful substrate area in comparison to conventional evaporation. This is not compatible to the needs of a high throughput production. Most ion sources use hot filament cathodes and extraction grids with limited life time especially when introducing oxygen into the ion source. Many oxides require ionized oxygen during film deposition in order to get fully oxidized films with low absorption losses and high packing densities. With the newly developed high power plasma ion assisted deposition we have overcome these problems. This paper mainly discusses the performance specification of plasma source (GIS)

technology and quality of TiO

2

coatings and the technology for antireflection coatings deposited with plasma-IAD.We can draw a conclusion that the refractive index of TiO

2

film will have different values with the anode current changing and they are 2.25

2.37

2.39

2.42 and 2.43 at wavelength of 520nm respectively. The reflectance of the antireflection coating is lower than 2% in the wavelength range between 450nm and 750nm.