Local topographical changes of Ge-(Sb)-Se thin films induced by direct electron beam writing

Abstract

Local topographical changes are studied in Ge-Se and Ge-Sb-Se thin films induced by focused electron beam exposure. The results show that under comparable experimental conditions, the Ge29.2Se70.8 film undergoes expansion, while in Ge-Sb-Se compositions (Ge17.9Sb16.6Se65.5, Ge11.4Sb22.9Se65.7), the material is preferentially removed instead. Variations in electron beam parameters, including exposure time, spot size, and magnification, as well as the thermodynamic state of the thin films (virgin vs. annealed), are studied to characterize their influence on material response (height/depth of micro-objects). Force spectroscopy (FS), atomic force microscopy (AFM), energy dispersive X-ray analysis (EDX) and digital holographic microscopy (DHM) are used to characterize the micro-objects created and to identify possible changes in stiffness and chemical composition of the films studied. Observed findings demonstrate that electron beam direct writing can be used to locally modify the surface of Ge-(Sb)-Se thin films, enabling the fabrication of micro-optical elements such as microlenses.