Lukaniuk M. Transient and reversible photo-stimulated transformations in films of chalcogenide vitreous semiconductors and interference lithography on their basis.

The thesis describes the results of the research of photoinduced effects such as successive positive photoresistive process and photoetching effect which are observed in annealed thin films of chalcogenide vitreous semiconductors, or, in other words, chalcogenide glasses (ChGs). The effect of photoetching in annealed ChG films has been described. The essence of this effect is the photostimulated increasing of the solubility of the exposured areas of ChG films at simultaneous exposure and etching. It has been established that the photoetching effect is based on transient changes in thin ChG films, which exist during irradiation only and disappear rapidly after switching off, at the same time, the basis of the successive photoresistive process is reversible photochanging. The phenomenology has been investigated and the mechanisms of the investigated photoetching and successive photoresistive effects in annealed ChG films have been proposed. Photoresist based on photo-etching and successive photoresist etching effects have been developed, and the technology of interference photolithography using these photoresists has been implemented.It has been demonstrated that application of processes on transient and reversible photostimulated transformations in annealed ChG layers in interference lithography allows to use more environmentally friendly non-organic photoresists on the basis of germanium-containing chalcogenide compounds to obtain periodic 1-D and 2-D structures with high quality surface and homogeneity on large scale substrates. Combining the methods of interference lithography and immersion with the usage of photoresists based on annealed ChG films allows to form structures with nanosized elements. The developed lithographic processes enable to form various periodic structures, in particular, diffraction periodic structures, subwave metal structures, microprofiliated plates, plasmonic structures (sensor chips with high sensitivity) on large scale substrates, and optical track records.