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Khomenkova L, Lehninger D, Kondratenko O, Ponomaryov S, Gudymenko O, Tsybrii Z, Yukhymchuk V, Kladko V, von Borany J, Heitmann J. Effect of Ge Content on the Formation of Ge Nanoclusters in Magnetron-Sputtered GeZrO x-Based Structures. NANOSCALE RESEARCH LETTERS 2017; 12:196. [PMID: 28314364 PMCID: PMC5355413 DOI: 10.1186/s11671-017-1960-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 02/27/2017] [Indexed: 06/06/2023]
Abstract
Ge-rich ZrO2 films, fabricated by confocal RF magnetron sputtering of pure Ge and ZrO2 targets in Ar plasma, were studied by multi-angle laser ellipsometry, Raman scattering, Auger electron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction for varied deposition conditions and annealing treatments. It was found that as-deposited films are homogeneous for all Ge contents, thermal treatment stimulated a phase separation and a formation of crystalline Ge and ZrO2. The "start point" of this process is in the range of 640-700 °C depending on the Ge content. The higher the Ge content, the lower is the temperature necessary for phase separation, nucleation of Ge nanoclusters, and crystallization. Along with this, the crystallization temperature of the tetragonal ZrO2 exceeds that of the Ge phase, which results in the formation of Ge crystallites in an amorphous ZrO2 matrix. The mechanism of phase separation is discussed in detail.
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Affiliation(s)
- L. Khomenkova
- V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, 45 Pr.Nauky, 03028 Kyiv, Ukraine
| | - D. Lehninger
- Institute of Applied Physics, TU Bergakademie Freiberg, D-09596 Freiberg, Germany
| | - O. Kondratenko
- V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, 45 Pr.Nauky, 03028 Kyiv, Ukraine
| | - S. Ponomaryov
- V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, 45 Pr.Nauky, 03028 Kyiv, Ukraine
| | - O. Gudymenko
- V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, 45 Pr.Nauky, 03028 Kyiv, Ukraine
| | - Z. Tsybrii
- V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, 45 Pr.Nauky, 03028 Kyiv, Ukraine
| | - V. Yukhymchuk
- V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, 45 Pr.Nauky, 03028 Kyiv, Ukraine
| | - V. Kladko
- V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, 45 Pr.Nauky, 03028 Kyiv, Ukraine
| | - J. von Borany
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden, Germany
| | - J. Heitmann
- Institute of Applied Physics, TU Bergakademie Freiberg, D-09596 Freiberg, Germany
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Korsunska N, Khomenkova L, Kolomys O, Strelchuk V, Kuchuk A, Kladko V, Stara T, Oberemok O, Romanyuk B, Marie P, Jedrzejewski J, Balberg I. Si-rich Al2O3 films grown by RF magnetron sputtering: structural and photoluminescence properties versus annealing treatment. NANOSCALE RESEARCH LETTERS 2013; 8:273. [PMID: 23758885 PMCID: PMC3680024 DOI: 10.1186/1556-276x-8-273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Accepted: 05/06/2013] [Indexed: 06/02/2023]
Abstract
Silicon-rich Al2O3 films (Six(Al2O3)1-x) were co-sputtered from two separate silicon and alumina targets onto a long silicon oxide substrate. The effects of different annealing treatments on the structure and light emission of the films versus x were investigated by means of spectroscopic ellipsometry, X-ray diffraction, micro-Raman scattering, and micro-photoluminescence (PL) methods. The formation of amorphous Si clusters upon the deposition process was found for the films with x ≥ 0.38. The annealing treatment of the films at 1,050°C to 1,150°C results in formation of Si nanocrystallites (Si-ncs). It was observed that their size depends on the type of this treatment. The conventional annealing at 1,150°C for 30 min of the samples with x = 0.5 to 0.68 leads to the formation of Si-ncs with the mean size of about 14 nm, whereas rapid thermal annealing of similar samples at 1,050°C for 1 min showed the presence of Si-ncs with sizes of about 5 nm. Two main broad PL bands were observed in the 500- to 900-nm spectral range with peak positions at 575 to 600 nm and 700 to 750 nm accompanied by near-infrared tail. The low-temperature measurement revealed that the intensity of the main PL band did not change with cooling contrary to the behavior expected for quantum confined Si-ncs. Based on the analysis of PL spectrum, it is supposed that the near-infrared PL component originates from the exciton recombination in the Si-ncs. However, the most intense emission in the visible spectral range is due to either defects in matrix or electron states at the Si-nc/matrix interface.
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Affiliation(s)
- Nadiia Korsunska
- V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028, Kyiv, Ukraine
| | - Larysa Khomenkova
- V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028, Kyiv, Ukraine
- CIMAP (CEA/CNRS/Ensicaen/UCBN), 6 Boulevard Marechal Juin, 14050, Caen, France
| | - Oleksandr Kolomys
- V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028, Kyiv, Ukraine
| | - Viktor Strelchuk
- V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028, Kyiv, Ukraine
| | - Andrian Kuchuk
- V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028, Kyiv, Ukraine
| | - Vasyl Kladko
- V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028, Kyiv, Ukraine
| | - Tetyana Stara
- V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028, Kyiv, Ukraine
| | - Oleksandr Oberemok
- V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028, Kyiv, Ukraine
| | - Borys Romanyuk
- V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauky, 03028, Kyiv, Ukraine
| | - Philippe Marie
- CIMAP (CEA/CNRS/Ensicaen/UCBN), 6 Boulevard Marechal Juin, 14050, Caen, France
| | | | - Isaac Balberg
- Racah Institute of Physics, Hebrew University, 91904, Jerusalem, Israel
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An Y, Labbé C, Khomenkova L, Morales M, Portier X, Gourbilleau F. Microstructure and optical properties of Pr3+-doped hafnium silicate films. NANOSCALE RESEARCH LETTERS 2013; 8:43. [PMID: 23336520 PMCID: PMC3562245 DOI: 10.1186/1556-276x-8-43] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 12/23/2012] [Indexed: 06/01/2023]
Abstract
In this study, we report on the evolution of the microstructure and photoluminescence properties of Pr3+-doped hafnium silicate thin films as a function of annealing temperature (TA). The composition and microstructure of the films were characterized by means of Rutherford backscattering spectrometry, spectroscopic ellipsometry, Fourier transform infrared absorption, and X-ray diffraction, while the emission properties have been studied by means of photoluminescence (PL) and PL excitation (PLE) spectroscopies. It was observed that a post-annealing treatment favors the phase separation in hafnium silicate matrix being more evident at 950°C. The HfO2 phase demonstrates a pronounced crystallization in tetragonal phase upon 950°C annealing. Pr3+ emission appeared at TA = 950°C, and the highest efficiency of Pr3+ ion emission was detected upon a thermal treatment at 1,000°C. Analysis of the PLE spectra reveals an efficient energy transfer from matrix defects towards Pr3+ ions. It is considered that oxygen vacancies act as effective Pr3+ sensitizer. Finally, a PL study of undoped HfO2 and HfSiOx matrices is performed to evidence the energy transfer.
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Affiliation(s)
- YongTao An
- CIMAP, UMR 6252 CNRS/CEA/Ensicaen/UCBN, 6 Boulevard Maréchal Juin, Caen, Cedex 4, 14050, France
| | - Christophe Labbé
- CIMAP, UMR 6252 CNRS/CEA/Ensicaen/UCBN, 6 Boulevard Maréchal Juin, Caen, Cedex 4, 14050, France
| | - Larysa Khomenkova
- CIMAP, UMR 6252 CNRS/CEA/Ensicaen/UCBN, 6 Boulevard Maréchal Juin, Caen, Cedex 4, 14050, France
| | - Magali Morales
- CIMAP, UMR 6252 CNRS/CEA/Ensicaen/UCBN, 6 Boulevard Maréchal Juin, Caen, Cedex 4, 14050, France
| | - Xavier Portier
- CIMAP, UMR 6252 CNRS/CEA/Ensicaen/UCBN, 6 Boulevard Maréchal Juin, Caen, Cedex 4, 14050, France
| | - Fabrice Gourbilleau
- CIMAP, UMR 6252 CNRS/CEA/Ensicaen/UCBN, 6 Boulevard Maréchal Juin, Caen, Cedex 4, 14050, France
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Khomenkova L, Sahu BS, Slaoui A, Gourbilleau F. Hf-based high-k materials for Si nanocrystal floating gate memories. NANOSCALE RESEARCH LETTERS 2011; 6:172. [PMID: 21711676 PMCID: PMC3211225 DOI: 10.1186/1556-276x-6-172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 02/24/2011] [Indexed: 05/19/2023]
Abstract
Pure and Si-rich HfO2 layers fabricated by radio frequency sputtering were utilized as alternative tunnel oxide layers for high-k/Si-nanocrystals-SiO2/SiO2 memory structures. The effect of Si incorporation on the properties of Hf-based tunnel layer was investigated. The Si-rich SiO2 active layers were used as charge storage layers, and their properties were studied versus deposition conditions and annealing treatment. The capacitance-voltage measurements were performed to study the charge trapping characteristics of these structures. It was shown that with specific deposition conditions and annealing treatment, a large memory window of about 6.8 V is achievable at a sweeping voltage of ± 6 V, indicating the utility of these stack structures for low-operating-voltage nonvolatile memory devices.
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Affiliation(s)
- Larysa Khomenkova
- CIMAP, UMR CNRS/CEA/ENSICAEN/UCBN 6252, Ensicaen, 6 Bd Mal Juin, 14050 Caen Cedex 4, France
| | - Bhabani S Sahu
- InESS/UDS-CNRS, 23 rue du Loess, 67037 Strasbourg, France
| | | | - Fabrice Gourbilleau
- CIMAP, UMR CNRS/CEA/ENSICAEN/UCBN 6252, Ensicaen, 6 Bd Mal Juin, 14050 Caen Cedex 4, France
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