Multilayer optical filters control by multi‐channel kinetic ellipsometry

Abstract

The use of multi‐wavelength kinetic ellipsometry control for the deposition of multilayer filters is presented. Two different control methods are described and their use for the fabrication of different types of optical filters is illustrated. We fit the ellipsometric data with a model and adjust the physical thickness during deposition to ensure the conservation of the optical thickness. In order to illustrate this method and to show its importance in the case of periodic structures or single layer control, a Bragg mirror and a resonator layer in a Fabry‐Perot filter were grown using Matrix Distributed Electron Cyclotron Resonance Plasma Enhanced Chemical Vapor Deposition (MDECR‐PECVD). The use of fitting both the index and thickness for control of the physical thickness is also shown. The importance of this method for manufacturing non‐periodic multilayer structures is demonstrated by the controlled deposition of an antireflection coating. The different features of these two methods are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)