Planar chalcogenide glass device processing

Glass thin film depositions are performed via thermal evaporation or RF magnetron sputtering, using a custom-designed film deposition station. The flexible techniques can be adapted to a wide range of glass film compositions, and are particular suitable for low-cost, high-throughput depositions on large-area substrates [1].

The device fabrication process uses standard UV lithography and a CMOS-backend-compatible lift-off technique we developed at MIT. This etch-free approach presents several benefits: leverages Si-CMOS process compatibility; enables submicron photonic device fabrication; reduces sidewall roughness; and applies to a wide choice of glass compositions [2-3]. Further, a surface tension induced thermal reflow process has been developed to remove as-fabricated device sidewall roughness and reduce optical loss [4].

Several chalcogenide glass photonic devices featuring world-record performance have been created, including high-index-contrast submicron photonic wire waveguides, multi-mode interferometer (MMI) splitters, and micro-ring and micro-disk resonators [5].