Reactive magnetron sputter technologies for precision optical and antireflective coatings on glass and polymer substrates

Reactive pulse magnetron sputtering of a metal target in a reactive gas atmosphere is used for depositing silica, alumina, niobium oxide and tantalum oxide films for optical applications. In stationary coating the precise control of gas flow and process conditions during reactive sputtering of a silicon target in a mixture of oxygen and nitrogen gas furthermore allows depositing layer systems with stepwise or gradient variation of the refractive index. In the paper the dependencies of film roughness and stress on process pressure are investigated. Coating at low pressure results in films with low roughness and strong compressive stress. Adhesion and durability are investigated for multilayer and antireflective coatings. Multilayer coatings on glass substrates with very low roughness and high durability are achieved at low deposition pressure. During coating of polymer substrates an intermediate process pressure allows achieving both good adhesion and high durability