RF magnetron sputtering deposition of multilayers optical filters for ultra-broadband applications with a large number of thin layers

TL;DR

This paper reports on advanced RF magnetron sputtering techniques for creating ultra-broadband optical filters with over 100 layers, emphasizing improved reliability and precise control through in situ monitoring and optical characterization.

Contribution

It introduces improved deposition methods and in situ optical monitoring for multilayer optical filters, enabling the fabrication of complex structures with over 100 layers.

Findings

Enhanced manufacturing reliability for multilayer optical filters.

Successful development of filters with more than 100 layers.

Improved control over layer properties through in situ monitoring.

Abstract

We present recent achievement on manufacturing optical filter and multilayers done with two complementary RF magnetron sputtering approaches: deposition duration control and in situ optical reflectance monitoring. Those approaches were greatly improved thanks to ellipsometry and spectrophotometry cross-studies of optical refractive indexes of Nb2O5, TiO2 and SiO2 materials grown using two sputtering systems. At the same time, we conducted deposition studies of these three materials which have increased the manufacturing reliability and allowed us to consider developing complex optical multilayers with more than 100 layers.