Structural Rearrangement of a-SiOx:H Films with Pulse Photon Annealing

Amorphous SiOx films with silicon nanoclusters are a new interesting material from the standpoint of the physics, technology, and possible practical applications, since such films can exhibit photoluminescence due to size quantization. Moreover, the optical properties of these structures can be controlled by varying the size and the content of silicon nanoclusters in the SiOx film, as well as by transforming nanoclusters into nanocrystals by means of high-temperature annealing. However, during the annealing of nonstoichiometric silicon oxide, significant changes can occur in the phase composition and the structure of the films. The results of investigations on the crystallization of silicon nanoclusters in a SiOx matrix have shownthat, even a very fast method of annealing using PPA leads to the formation of large silicon crystallites. This also causes the crystallization of at least a part of the oxide phase in the form of silicon hydroxide H6O7Si2. Moreover, in films with an initial content of pure silicon nanoclusters ≤ 50%, during annealing a part of the silicon is spent on the formation of oxide, and part of it is spent on the formation of silicon crystals. While in a film with an initial concentration of silicon nanoclusters ≥ 53%, on the contrary, upon annealing, there occurs a partial transition of silicon from the oxide phase to the growth ofSi crystals Reference 1. Undalov Y. K., Terukov E. I., Silicon nanoclustersncl-Si in a hydrogenated amorphous silicon suboxidematrix a-SiOx:H (0 < x < 2). Semiconductors. 2015;49(7):867- 878. DOI: https://doi.org/10.1134/S10637826150702222. Kim K. H., Johnson E. V., Kazanskii A. G.,Khenkin M. V., Roca P. Unravelling a simple methodfor the low temperature synthesis of siliconnanocrystals and monolithic nanocrystalline thinfilms. Scientific Reports. 2017;7(1) DOI: https://doi.org/10.1038/srep405533. Undalov Y. K., Terukov E. I., Trapeznikova I. 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THE NANOCRYSTALS SIZE ESTIMATION USING RAMAN SPECTROSCOPY IN A-SIOX:H FILMS AFTER CRYSTALLIZATION OF SILICON NANOCLUSTERS

The a-SiOx thin films with silicon nanoclusters are currently being actively studied by various laboratories due to the possibility of efficient control of their optical properties, both at the stage of formation and using technological treatments. The presence of excess silicon in such films leads to the growth of nanocrystals during high-temperature annealing, which affects the optical properties of SiOx films, including photoluminescence. Therefore, in this work, we studied the formation of silicon nanocrystals in a-SiOx films during Pulse Photon Annealing (PPA). X-ray diffraction studies of SiOx films with different silicon contents have shown that, upon PPA annealing, arrays of silicon nanocrystals of significantly different average sizes are formed. Moreover, according to the Raman spectroscopy data, PPA does not lead to complete ordering of the structural network of silicon atoms, and some of the atoms, apparently located in small clusters of ~1 nm, retain deviations from interatomic distances and bond angles.

Влияние кислородных вакансий на формирование и структуру филамента в мемристорах на основе диоксида кремния

The improvement of the parameters of the SiO2-based memristor is found when creating displacement cascades in the near-surface layer of a silicon dioxide film by irradiation with Xe+ ions. Molecular dynamic modeling of the structure of amorphous SiO2 enriched with oxygen vacancies has shown the possibility of nucleation of silicon nanoclusters, which can play a significant role in the formation and evolution of current conducting paths (filaments) and thereby affect the parameters of the memristor.