Patterning chalcogenide glass by direct resist-free thermal nanoimprint

In this article, patterning As2S3 chalcogenide glass is investigated from a nanoimprint perspective. Thermal nanoimprint was used to successfully pattern As2S3 microstructures. Due to the high melt viscosity of As2S3, patterns of a few microns and submicrons can be well formed, while larger patterns cannot be faithfully replicated due to limited melt flow when a thin initial film is used. Accelerated crystallite formation after nanoimprint was observed and a method to suppress crystallites was explored. In patterned As2S3 microstructures, optical birefringence was observed near the pattern edges, which potentially has a significant impact on the optical properties of patterned microstructures. It was also observed that significant surfactant wear occurs after just a few nanoimprints. A new surfactant with better temperature stability was proposed and its durability was compared to commonly used nanoimprint surfactant such as heptadecafluoro-1,1,2,2-tetrahydrodecyl trichlorosilane.