Etchless pedestal chalcogenide waveguide platform for long-wave IR applications

Abstract

We report the fabrication of GeAsSeTe/GeAsSe waveguides using a simple and cost-effective process. Chalcogenides are very delicate materials and can be degraded when in contact with developer solutions during photolithography and when processed using common etchants, making the use of conventional fabrication processes unattractive. In order to avoid any post-film deposition processing for the fabrication of chalcogenide waveguides, we pre-patterned pedestal structures on silicon substrates using photolithography and a simple wet-etch process followed by the deposition of chalcogenide films on the patterned structures. Using the scattered light decay fitting method, we estimated waveguide propagation losses averaging approximately 0.9 dB/cm for wavelengths between 7 and 11 µm. With these findings we show that this waveguide platform is a very attractive candidate for long-wave infrared applications.