Fabrication of ternary Ge-Se-Sb chalcogenide microlens arrays using thermal reflow

Ternary Ge-Se-Sb chalcogenide glasses have attractive optical properties for fabrication of micro optical components. This paper reports a thermal reflow method to fabricate Ge-Se-Sb chalcogenide microlens arrays (MLAs). By heating the chalcogenide to melting state, the surface tension of the melting chalcogenide contracts the liquid chalcogenide into spherical shape, forming microlenses automatically. Key processes including chalcogenide evaporation, dry etching, and thermal reflow temperature and time are investigated systematically, and microlenses with smooth surfaces, uniform profiles, and small F numbers have been fabricated successfully using the optimized processes. These preliminary results demonstrate the feasibility of using thermal reflow as a simple and low cost method to fabricate Ge-Se-Sb chalcogenide microlenses. The process parameters and the key influencing factors can be used as a baseline for process optimization.