Registration Number
0224U032996,
(0124U003756)
, R & D reports
Title
Deformation engineering of the electronic structure of GeSn thin films for new generation IR optoelectronics
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Розробка методики магнетронного осадження GeSn плівок на Si та Ge підкладки при варіюванні в них вмісту Sn
Head
Yukhymchuk Volodymyr O., д.ф.-м.н.
Registration Date
13-12-2024
Organization
V. Lashkaryov Institute of Semiconductor Physics of National Academy
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Development of physico-technological principles of strain engineering of thin GeSn films for optoelectronics in the near and mid-IR range, namely, creation of working physical models of changes in the fundamental properties of Ge films due to the simultaneous incorporation of Sn and C or B atoms into their lattice in the process of magnetron sputtering of the corresponding targets and by ion implantation of Sn and C (B) ions in Ge and GeSn films and post-growth thermal treatments.
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Using the empirical pseudo-potential method, theoretical modeling of the change in the bandgap width of Ge1-xSnx films depending on the Sn content in them was carried out. Based on the developed model, the proportion of Sn (12 at.%) in the Ge lattice, at which transitions to the direct-gap electronic structure are possible, was estimated. It was established that the addition of C atoms (0.08 at.%) significantly reduces the proportion of Sn atoms (4.5 at.%) required for such a transition. For the formation of GeSn and GeSn:C films by magnetron sputtering, appropriate targets were manufactured. Using XRD and Raman spectroscopy, it was established that immediately after the deposition of GeSn and GeSn:C films are amorphous. Using SIMS diagnostics, the diffusion processes of incorporated atoms in GeSn and GeSn:C films were studied when varying their annealing temperature from 200 оС to 550 °C and time from 1 min. up to 8 hours. It was found that during high-temperature annealing (500 °C and above) part of Sn and C atoms diffuses to the Si substrate/Ge buffer layer interface and to the surface of the films. Thermal (photonic) annealing of GeSn and GeSn:С films leads to their crystallization at 500 оС and 550 °C, respectively. It was found that an increase in the Sn fraction in the film significantly reduces the crystallization temperature, which is due to the influence of Sn atoms on the activation energy of Ge atoms during the crystallization process. It was shown that laser annealing of GeSn:С films allows the formation of polycrystalline films with a significantly higher Sn content compared to thermal annealing. The latter is due to the fact that strong local heating in GeSn and GeSn:C films creates non-equilibrium conditions under which Sn and C atoms diffuse into this region from colder regions of the film. The elemental composition of GeSn and GeSn:C films, which are 2 and 8 at.%, respectively, at 10 at.% Sn in the target.
Product Description
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Yefanov Volodymyr S.
Hudymenko Oleksandr Yo.
Kapush Olha A.
Mazur Nazar V.
Sabov Tomash M.
Tarasov Heorhii H.
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2024-12-13
