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Dirko VV, Lozovoy KA, Kokhanenko AP, Kukenov OI, Korotaev AG, Voitsekhovskii AV. Peculiarities of the 7 × 7 to 5 × 5 Superstructure Transition during Epitaxial Growth of Germanium on Silicon (111) Surface. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:231. [PMID: 36677983 PMCID: PMC9862873 DOI: 10.3390/nano13020231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/30/2022] [Accepted: 12/30/2022] [Indexed: 06/17/2023]
Abstract
This paper presents the results of studying the processes of epitaxial growth of germanium on silicon with crystallographic orientation (111) in a wide temperature range. The temperature dependences of the duration of the transition stage from the 7 × 7 to 5 × 5 superstructure and the values of the critical thickness of the transition from two-dimensional to three-dimensional growth in the range from 250 to 700 °C are determined using the reflection high-energy electron diffraction method. It was shown for the first time that the transition time from the 7 × 7 superstructure to 5 × 5 superstructure depends on the temperature of epitaxial growth. The region of low temperatures of synthesis, which has received insufficient attention so far, is also considered.
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Shklyaev AA, Latyshev AV. Dewetting behavior of Ge layers on SiO 2 under annealing. Sci Rep 2020; 10:13759. [PMID: 32792554 PMCID: PMC7426840 DOI: 10.1038/s41598-020-70723-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 07/27/2020] [Indexed: 11/09/2022] Open
Abstract
The solid-state dewetting phenomenon in Ge layers on SiO2 is investigated as a function of layer thickness dGe (from 10 to 86 nm) and annealing temperature. The dewetting is initiated at about 580-700 °C, depending on dGe, through the appearance of surface undulation leading to the particle formation and the rupture of Ge layers by narrow channels or rounded holes in the layers with the thicknesses of 10-60 and 86 nm, respectively. The channel widths are significantly narrower than the distance between the particles that causes the formation of thinned Ge layer areas between particles at the middle dewetting stage. The thinned areas are then agglomerated into particles of smaller sizes, leading to the bimodal distributions of the Ge particles which are different in shape and size. The existence of a maximum in the particle pair correlation functions, along with the quadratic dependence of the corresponding particle spacing on dGe, may indicate the spinodal mechanism of the dewetting in the case of relatively thin Ge layers. Despite the fact that the particle shape, during the solid-state dewetting, is not thermodynamically equilibrium, the use of the Young's equation and contact angles allows us to estimate the particle/substrate interface energy.
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Affiliation(s)
- A A Shklyaev
- A.V. Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk, 630090, Russia.
| | - A V Latyshev
- A.V. Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk, 630090, Russia
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Zhachuk R, Coutinho J, Palotás K. Atomic and electronic structure of the Si(331)-(12 × 1) surface. J Chem Phys 2018; 149:204702. [PMID: 30501252 DOI: 10.1063/1.5048064] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report on the investigation of the atomic and electronic structures of a clean Si(331)-(12 × 1) surface using a first-principles approach with both plane wave and strictly localized basis sets. Starting from the surface structure proposed by Zhachuk and Teys [Phys. Rev. B 95, 041412(R) (2017)], we develop significant improvements to the atomic model and localized basis set which are critical for the correct description of the observed bias dependence of scanning tunneling microscopy (STM) images. The size mismatch between the Si pentamers from the surface model and those seen by STM is explained within the context of the Tersoff-Hamann model. The energy barriers that separate different Si(331) buckled configurations were estimated, showing that the surface structure is prone to dynamic buckling at room temperature. It is found that empty electronic states on Si(331) are essentially localized on the pentamers with interstitials and under-coordinated Si sp 2-like atoms between them, while filled electronic states are localized on under-coordinated Si sp 3-like atoms and dimers on trenches. The calculated electronic density of states exhibits two broad peaks in the fundamental bandgap of Si: one near the valence band top and the other near the conduction band bottom. The resulting surface bandgap of 0.58 eV is in an excellent agreement with spectroscopy studies.
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Affiliation(s)
- Ruslan Zhachuk
- Institute of Semiconductor Physics, Pr. Lavrentyeva 13, Novosibirsk 630090, Russia
| | - José Coutinho
- Department of Physics and I3N, University of Aveiro, Campus Santiago, 3810-193 Aveiro, Portugal
| | - Krisztián Palotás
- Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 84511 Bratislava, Slovakia
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Gallet JJ, Silly MG, Kazzi ME, Bournel F, Sirotti F, Rochet F. Chemical and kinetic insights into the Thermal Decomposition of an Oxide Layer on Si(111) from Millisecond Photoelectron Spectroscopy. Sci Rep 2017; 7:14257. [PMID: 29079787 PMCID: PMC5660199 DOI: 10.1038/s41598-017-14532-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/11/2017] [Indexed: 11/08/2022] Open
Abstract
Despite thermal silicon oxide desorption is a basic operation in semiconductor nanotechnology, its detailed chemical analysis has not been yet realized via time-resolved photoemission. Using an advanced acquisition system and synchrotron radiation, heating schedules with velocities as high as 100 K.s-1 were implemented and highly resolved Si 2p spectra in the tens of millisecond range were obtained. Starting from a Si(111)-7 × 7 surface oxidized in O2 at room temperature (1.4 monolayer of oxygen), changes in the Si 2p spectral shape enabled a detailed chemical analysis of the oxygen redistribution at the surface and of the nucleation, growth and reconstruction of the clean silicon areas. As desorption is an inhomogeneous surface process, the Avrami formalism was adapted to oxide desorption via an original mathematical analysis. The extracted kinetic parameters (the Avrami exponent equal to ~2, the activation energy of ~4.1 eV and a characteristic frequency) were found remarkably stable within a wide (~110 K) desorption temperature window, showing that the Avrami analysis is robust. Both the chemical and kinetic information collected from this experiment can find useful applications when desorption of the oxide layer is a fundamental step in nanofabrication processes on silicon surfaces.
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Affiliation(s)
- J-J Gallet
- Sorbonne Universités, UPMC Univ. Paris 06, and CNRS UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement (LCPMR), F-75005, Paris, France
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192, Gif-sur-Yvette, France
| | - M G Silly
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192, Gif-sur-Yvette, France
| | - M El Kazzi
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192, Gif-sur-Yvette, France
- Paul Scherrer Institut, 5232, Villigen-PSI, Switzerland
| | - F Bournel
- Sorbonne Universités, UPMC Univ. Paris 06, and CNRS UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement (LCPMR), F-75005, Paris, France
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192, Gif-sur-Yvette, France
| | - F Sirotti
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192, Gif-sur-Yvette, France
- Laboratoire de Physique de la Matière Condensée, CNRS and Ecole Polytechnique, Université Paris Saclay, F- 91128, Palaiseau, France
| | - F Rochet
- Sorbonne Universités, UPMC Univ. Paris 06, and CNRS UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement (LCPMR), F-75005, Paris, France.
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192, Gif-sur-Yvette, France.
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