Surface morphology effects of post-implantation annealing in thin amorphous films of the As-Se system

The effects of ion implantation and subsequent annealing on the surface morphology of thin amorphous chalcogenide films of the As-Se system have been studied. Ion implantation of nitrogen (N⁺) with an energy E=100 keV and high doses (typically D=1.10¹⁶ cm⁻²) has been carried out at room temperature. Subsequent thermal annealing treatments near the melting temperature (T_g∼160°C) have been performed leading to changes in the thin-film morphology, which are dependent on the As content and are best expressed for the As₃Se₂ films. Optical microscope photographs reveal details of the rippled surface exhibiting quasi-regular domain-like structure. The parameter λ, describing it, is dependent on the film thickness and grows with its increase. Thermal annealing near T_g also influences the diffuse optical reflectivity—it increases considerably while the interference features tend to disappear with the appearance of the rippled film surface structure and the effect is again greater for the thicker films.