ION-ASSITED EVAPORATION

Ion-assisted evaporation is used mainly to deposit multilayer optical interference coatings for optical filtering and antireflection. We have designed such systems for R&D, the optical components industry, and the ophthalmic coatings industry.

Ion assisted evaporation (IAE) uses a broad beam ion source to direct an energetic, reactive (typically oxygen) ion beam simultaneous with the evaporation of metal or dielectric materials (typically using an electron beam) onto a substrate. The ion sources are usually of the “gridless,” end-Hall type. The ion beam is neutralized with an independent electron source. The desired film is frequently an alternating stack of high and low index of refraction materials of metal oxide composition like SiO₂, Al₂O₃, TiO₂, and Ta₂O₅.

The goal is to control the stability, density and optical properties of the deposited films. IAE allows the deposition of much higher quality optical films than is possible by evaporation alone.