AVS 50th International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeM

Paper TF-WeM1
Multilayer Optical Coatings Using Closed Field Magnetron Sputtering

Wednesday, November 5, 2003, 8:20 am, Room 329

Session: Optical Thin Films and Photovoltaics I
Presenter: J.M. Walls, Applied Multilayers Ltd, UK
Authors: J.M. Walls, Applied Multilayers Ltd, UK
D.G. Gibson, Applied Multilayers Ltd, UK
J. Hampshire, Applied Multilayers Ltd, UK
D.G. Teer, Applied Multilayers Ltd, UK
Correspondent: Click to Email
Magnetron Sputtering has many advantages for the deposition of multilayer optical coatings. The process operates at high energy producing dense, spectrally stable coatings. The sputtering process is also "cold", making it suitable for use on the widest range of substrates including polymers. This paper will describe a new process that allows high quality, multilayer metal-oxide thin films to be deposited at high rates using Closed Field magnetron sputtering together with pulsed dc power. The Closed Field process for optical coatings uses two or more different metal targets. The target is held in a partially oxidised state controlled using plasma emission monitoring and the oxidation occurs in the entire volume around the rotating substrate carrier. In addition to describing the new process, this paper will discuss the optical properties of individual layers and their application to a range of multilayer precision optical coatings. The ion current density and the low bias voltage provided by Closed Field magnetron sputtering produces films at a high rate with excellent optical properties. Machines based on the Closed Field are scaleable to meet a range of batch size requirements. Examples of multilayer coatings in the visible and infra-red spectra will be provided. Examples in the visible spectrum will include Anti-reflective and other coatings using fully oxidised SiO2, TiO2 ITO and other metal-oxide films. Applications in the infra-red will incorporate materials such as Si, Si3N4 and TiO2. Typically, thin film thickness control is accomplished simply using time although quartz crystal monitoring or optical monitoring are used for more demanding applications. Fine layer thickness control is also assisted with a specially designed rotating shutter mechanism.