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Rad ZJ, Lehtiö JP, Mack I, Rosta K, Chen K, Vähänissi V, Punkkinen M, Punkkinen R, Hedman HP, Pavlov A, Kuzmin M, Savin H, Laukkanen P, Kokko K. Decreasing Interface Defect Densities via Silicon Oxide Passivation at Temperatures Below 450 °C. ACS APPLIED MATERIALS & INTERFACES 2020; 12:46933-46941. [PMID: 32960564 DOI: 10.1021/acsami.0c12636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low-temperature (LT) passivation methods (<450 °C) for decreasing defect densities in the material combination of silica (SiOx) and silicon (Si) are relevant to develop diverse technologies (e.g., electronics, photonics, medicine), where defects of SiOx/Si cause losses and malfunctions. Many device structures contain the SiOx/Si interface(s), of which defect densities cannot be decreased by the traditional, beneficial high temperature treatment (>700 °C). Therefore, the LT passivation of SiOx/Si has long been a research topic to improve application performance. Here, we demonstrate that an LT (<450 °C) ultrahigh-vacuum (UHV) treatment is a potential method that can be combined with current state-of-the-art processes in a scalable way, to decrease the defect densities at the SiOx/Si interfaces. The studied LT-UHV approach includes a combination of wet chemistry followed by UHV-based heating and preoxidation of silicon surfaces. The controlled oxidation during the LT-UHV treatment is found to provide an until now unreported crystalline Si oxide phase. This crystalline SiOx phase can explain the observed decrease in the defect density by half. Furthermore, the LT-UHV treatment can be applied in a complementary, post-treatment way to ready components to decrease electrical losses. The LT-UHV treatment has been found to decrease the detector leakage current by a factor of 2.
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Affiliation(s)
- Zahra Jahanshah Rad
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Juha-Pekka Lehtiö
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Iris Mack
- Department of Electronics and Nanoengineering, Aalto University, FI-02150 Espoo, Finland
| | - Kawa Rosta
- Department of Electronics and Nanoengineering, Aalto University, FI-02150 Espoo, Finland
| | - Kexun Chen
- Department of Electronics and Nanoengineering, Aalto University, FI-02150 Espoo, Finland
| | - Ville Vähänissi
- Department of Electronics and Nanoengineering, Aalto University, FI-02150 Espoo, Finland
| | - Marko Punkkinen
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Risto Punkkinen
- Department of Future Technologies, University of Turku, FI-20014 Turku, Finland
| | - Hannu-Pekka Hedman
- Department of Future Technologies, University of Turku, FI-20014 Turku, Finland
| | - Andrei Pavlov
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Mikhail Kuzmin
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
- Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021, Russian Federation
| | - Hele Savin
- Department of Electronics and Nanoengineering, Aalto University, FI-02150 Espoo, Finland
| | - Pekka Laukkanen
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Kalevi Kokko
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
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Belov IV. Application of Empirical Si–O–C Potential to Simulate Amorphous Atomic Structures and Transition Layers by the Bond Switching Method. CRYSTALLOGR REP+ 2019. [DOI: 10.1134/s1063774519040059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Abstract
The state of oxygen in aqueous supersaturated solutions prepared by different methods was studied using high-resolution ultrasonic spectroscopy in combination with other techniques. This allowed for nondestructive evaluation of the properties of oxygen solute particles, composed of oxygen molecules and surrounding (coordinating) molecules of water, at equilibrium, supersaturated conditions, and different temperatures and concentrations of O2. The results were compared with the behaviors of other types of solutes in water, including H2O2, which has similar molecular size and mass to O2 but is characterized by a significantly different type of interaction with water molecules. Additionally, theoretical modeling was performed to assess the ultrasonic characteristics of dispersions of oxygen nanobubbles stabilized by a surface electrical charge. The obtained data indicate a clathrate-like organization of water in the coordination shells of single molecules of O2. We did not find any signs of formation of clusters of oxygen molecules in supersaturated solutions. No quantifiable presence of oxygen nanobubbles in the solutions was detected. The state of O2 molecules was not affected by supersaturation within the analyzed concentration range of oxygen. The results also demonstrated the potential of the ultrasonic technique in precision real-time nondestructive monitoring of oxygen solubilization and outgassing processes.
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Affiliation(s)
- Yuelong Li
- School of Chemistry, College of Life Science , University College Dublin , Belfield Campus , Dublin 4 , Ireland
| | - Vitaly Buckin
- School of Chemistry, College of Life Science , University College Dublin , Belfield Campus , Dublin 4 , Ireland
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4
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Tuominen M, Mäkelä J, Yasir M, Dahl J, Granroth S, Lehtiö JP, Félix R, Laukkanen P, Kuzmin M, Laitinen M, Punkkinen MPJ, Hedman HP, Punkkinen R, Polojärvi V, Lyytikäinen J, Tukiainen A, Guina M, Kokko K. Oxidation-Induced Changes in the ALD-Al 2O 3/InAs(100) Interface and Control of the Changes for Device Processing. ACS APPLIED MATERIALS & INTERFACES 2018; 10:44932-44940. [PMID: 30508372 DOI: 10.1021/acsami.8b17843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
InAs crystals are emerging materials for various devices like radio frequency transistors and infrared sensors. Control of oxidation-induced changes is essential for decreasing amounts of the harmful InAs surface (or interface) defects because it is hard to avoid the energetically favored oxidation of InAs surface parts in device processing. We have characterized atomic-layer-deposition (ALD) grown Al2O3/InAs interfaces, preoxidized differently, with synchrotron hard X-ray photoelectron spectroscopy (HAXPES), low-energy electron diffraction, scanning tunneling microscopy, and time-of-flight elastic recoil detection analysis. The chemical environment and core-level shifts are clarified for well-embedded InAs interfaces (12 nm Al2O3) to avoid, in particular, effects of a significant potential change at the vacuum-solid interface. High-resolution As 3d spectra reveal that the Al2O3/InAs interface, which was sputter-cleaned before ALD, includes +1.0 eV shift, whereas As 3d of the preoxidized (3 × 1)-O interface exhibits a shift of -0.51 eV. The measurements also indicate that an As2O3 type structure is not crucial in controlling defect densities. Regarding In 4d measurements, the sputtered InAs interface includes only a +0.29 eV shift, while the In 4d shift around -0.3 eV is found to be inherent for the crystalline oxidized interfaces. Thus, the negative shifts, which have been usually associated with dangling bonds, are not necessarily an indication of such point defects as previously expected. In contrast, the negative shifts can arise from bonding with O atoms. Therefore, specific care should be directed in determining the bulk-component positions in photoelectron studies. Finally, we present an approach to transfer the InAs oxidation results to a device process of high electron mobility transistors (HEMT) using an As-rich III-V surface and In deposition. The approach is found to decrease a gate leakage current of HEMT without losing the gate controllability.
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Affiliation(s)
- Marjukka Tuominen
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
| | - Jaakko Mäkelä
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
| | - Muhammad Yasir
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
| | - Johnny Dahl
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
| | - Sari Granroth
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
| | - Juha-Pekka Lehtiö
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
| | - Roberto Félix
- Renewable Energies , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , DE-14109 Berlin , Germany
| | - Pekka Laukkanen
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
| | - Mikhail Kuzmin
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
| | - Mikko Laitinen
- Department of Physics , University of Jyvaskyla , FI-40014 Jyväskylä , Finland
| | - Marko P J Punkkinen
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
| | - Hannu-Pekka Hedman
- Department of Future Technologies , University of Turku , FI-20014 Turku , Finland
| | - Risto Punkkinen
- Department of Future Technologies , University of Turku , FI-20014 Turku , Finland
| | - Ville Polojärvi
- Optoelectronics Research Centre , Tampere University of Technology , FI-33101 Tampere , Finland
| | - Jari Lyytikäinen
- Optoelectronics Research Centre , Tampere University of Technology , FI-33101 Tampere , Finland
| | - Antti Tukiainen
- Optoelectronics Research Centre , Tampere University of Technology , FI-33101 Tampere , Finland
| | - Mircea Guina
- Optoelectronics Research Centre , Tampere University of Technology , FI-33101 Tampere , Finland
| | - Kalevi Kokko
- Department of Physics and Astronomy , University of Turku , FI-20014 Turku , Finland
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5
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Salles N, Richard N, Mousseau N, Hemeryck A. Strain-driven diffusion process during silicon oxidation investigated by coupling density functional theory and activation relaxation technique. J Chem Phys 2017; 147:054701. [PMID: 28789535 DOI: 10.1063/1.4996206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The reaction of oxygen molecules on an oxidized silicon model-substrate is investigated using an efficient potential energy hypersurface exploration that provides a rich picture of the associated energy landscape, energy barriers, and insertion mechanisms. Oxygen molecules are brought in, one by one, onto an oxidized silicon substrate, and accurate pathways for sublayer oxidation are identified through the coupling of density functional theory to the activation relaxation technique nouveau, an open-ended unbiased reaction pathway searching method, allowing full exploration of potential energy surface. We show that strain energy increases with O coverage, driving the kinetics of diffusion at the Si/SiO2 interface in the interfacial layer and deeper into the bulk: at low coverage, interface reconstruction dominates while at high coverage, oxygen diffusion at the interface or even deeper into the bottom layers is favored. A changing trend in energetics is observed that favors atomic diffusions to occur at high coverage while they appear to be unlikely at low coverage. Upon increasing coverage, strain is accumulated at the interface, allowing the oxygen atom to diffuse as the strain becomes large enough. The observed atomic diffusion at the interface releases the accumulated strain, which is consistent with a layer-by-layer oxidation growth.
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Affiliation(s)
- N Salles
- LAAS CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - N Richard
- CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
| | - N Mousseau
- Département de Physique, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada
| | - A Hemeryck
- LAAS CNRS, Université de Toulouse, CNRS, Toulouse, France
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6
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Yang J, Fang H, Gao Y. Effect of Water Adsorption on the Photoluminescence of Silicon Quantum Dots. J Phys Chem Lett 2016; 7:1788-1793. [PMID: 27117881 DOI: 10.1021/acs.jpclett.6b00574] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The optical properties of silicon quantum dots (Si QDs) are strongly influenced by circumjacent surface-adsorbed molecules, which would highly affect their applications; however, water, as the ubiquitous environment, has not received enough attention yet. We employed the time-dependent density functional calculations to investigate the water effect of photoluminescence (PL) spectra for Si QDs. In contrast with the absorption spectra, PL spectra exhibit distinct characteristics. For Si32H38, PL presents the single maximum in the dry and humid environment, while the emission spectrum displays a dual-band fluorescence spectroscopy in the low-humidity environment. This phenomenon is also observed in the larger Si QDs. The distinct character in spectroscopy is dominated by the stretching of the Si-Si bond, which could be explained by the self-trapped exciton model. Our results shed light on the Si-water interaction that is important for the development of optical devices based on Si-coated surfaces.
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Affiliation(s)
- Jinrong Yang
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Haiping Fang
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
- Shanghai Science Research Center, Chinese Academy of Sciences , Shanghai 201204, China
| | - Yi Gao
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, China
- Shanghai Science Research Center, Chinese Academy of Sciences , Shanghai 201204, China
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7
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Tsetseris L, Pantelides ST. Oxygen migration, agglomeration, and trapping: key factors for the morphology of the Si-SiO(2) interface. PHYSICAL REVIEW LETTERS 2006; 97:116101. [PMID: 17025906 DOI: 10.1103/physrevlett.97.116101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Indexed: 05/12/2023]
Abstract
The measured activation energies for oxide growth rates at the initial and late stages of oxidation of Si are 2 and 1.2 eV, respectively. These values imply that oxidation can proceed at temperatures much smaller than the 800 degrees C normally used to obtain devices with exceptionally smooth Si-SiO2 interfaces. Here, we use first-principles calculations to identify the atomic-scale mechanisms of the 2 eV process and of additional processes with higher barriers that control the interface morphology and ultimately provide for smooth layer-by-layer oxide growth, as observed at high temperatures.
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Affiliation(s)
- L Tsetseris
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA
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8
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Borensztein Y, Pluchery O, Witkowski N. Probing the Si-Si dimer breaking of Si(100)2x1 surfaces upon molecule adsorption by optical spectroscopy. PHYSICAL REVIEW LETTERS 2005; 95:117402. [PMID: 16197046 DOI: 10.1103/physrevlett.95.117402] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Revised: 05/20/2005] [Indexed: 05/04/2023]
Abstract
The adsorption of atoms and molecules of several gases of the Si(100)2x1 silicon reconstructed surface is investigated by surface differential reflectance spectroscopy. This UV-visible optical spectroscopy makes possible the discrimination between two adsorption modes, depending on whether or not the adsorption leads to breaking the Si-Si dimers. The observation of two different optical features is assigned to the bonding on dangling bonds or to the breaking of dimers, and gives access to the adsorption mode of hydrogen, water, oxygen, and pyridine. Moreover, the technique being quantitative, we can determine the total amount of dimers involved in the adsorption and monitor the adsorption kinetics.
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Affiliation(s)
- Y Borensztein
- Institut des Nanosciences de Paris (UMR CNRS No. 7588), Universities Paris VI and Paris VII, 4 place Jussieu, F-75252 Paris cedex 05, France.
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9
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Hadjisavvas G, Kelires PC. Structure and energetics of Si nanocrystals embedded in a-SiO2. PHYSICAL REVIEW LETTERS 2004; 93:226104. [PMID: 15601104 DOI: 10.1103/physrevlett.93.226104] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Indexed: 05/24/2023]
Abstract
We develop realistic models of Si nanocrystals embedded in a-SiO2 using a Monte Carlo approach. The interface structure and its energetics are studied as a function of the nanocrystal size. We find that the low-energy geometries at the interface are Si-O-Si bridge bonds. Remarkably, their fraction strongly declines as the size becomes smaller. Concurrently, the embedding causes substantial deformation in such small nanocrystals. Based on these findings, an alternative explanation is given for the reduced optical gaps in this size regime.
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Affiliation(s)
- G Hadjisavvas
- Physics Department, University of Crete, P.O. Box 2208, 710 03, Heraclion, Crete, Greece
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10
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Dreiner S, Schürmann M, Westphal C. Structural analysis of the SiO2/Si100 interface by means of photoelectron diffraction. PHYSICAL REVIEW LETTERS 2004; 93:126101. [PMID: 15447281 DOI: 10.1103/physrevlett.93.126101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Indexed: 05/24/2023]
Abstract
The local environment of Si atoms at the interface between a thermally grown SiO2 film and Si(100) was studied by angle-scanned photoelectron diffraction. Experimental photoelectron diffraction patterns for each Si oxidation state were obtained from the results of least squares fitting on Si 2p core-level spectra. A comparison of the diffraction patterns with multiple-scattering calculations including an R-factor analysis was performed. An excellent agreement between experimental and simulated data was achieved within the proposed bridge-bonded interface model [Phys. Rev. Lett. 84, 4393 (2000)]].
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Affiliation(s)
- S Dreiner
- Universität Dortmund, Lehrstuhl für Experimentelle Physik I, Otto-Hahn-Strasse 4, 44221 Dortmund, Germany
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11
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Bongiorno A, Pasquarello A. Reaction of the oxygen molecule at the Si(100)-SiO2 interface during silicon oxidation. PHYSICAL REVIEW LETTERS 2004; 93:086102. [PMID: 15447201 DOI: 10.1103/physrevlett.93.086102] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2004] [Indexed: 05/24/2023]
Abstract
Using constrained ab initio molecular dynamics, we investigate the reaction of the O2 molecule at the Si(100)-SiO2 interface during Si oxidation. The reaction proceeds sequentially through the incorporation of the O2 molecule in a Si-Si bond and the dissociation of the resulting network O2 species. The oxidation reaction occurs nearly spontaneously and is exothermic, irrespective of the O2 spin state or of the amount of excess negative charge available at the interface. The reaction evolves through the generation of network coordination defects associated with charge transfers. Our investigation suggests that the Si oxidation process is fully governed by diffusion.
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Affiliation(s)
- Angelo Bongiorno
- Institut de Théorie des Phénomènes Physiques (ITP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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12
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Munkholm A, Brennan S. Ordering in thermally oxidized silicon. PHYSICAL REVIEW LETTERS 2004; 93:036106. [PMID: 15323842 DOI: 10.1103/physrevlett.93.036106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2004] [Indexed: 05/24/2023]
Abstract
We present new evidence and a model for residual ordering of silicon atoms within the oxide of thermally oxidized silicon wafers. X-ray scattering is used to observe the residual order in thermally grown SiO2 on Si(001), (011), and (111) surfaces with thicknesses of 60 to 1000 A, for both on-axis and miscut surfaces. In every case, the scattering position can be predicted using a model which expands the silicon lattice during oxidation without completely disordering it. The amount of expansion and disorder is dependent on the type of oxidation process employed.
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Affiliation(s)
- A Munkholm
- Stanford Synchrotron Radiation Laboratory, Stanford Linear Accelerator Center, Menlo Park, California 94025, USA
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13
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Cantin JL, von Bardeleben HJ, Shishkin Y, Ke Y, Devaty RP, Choyke WJ. Identification of the carbon dangling bond center at the 4H-SiC/SiO(2) interface by an EPR study in oxidized porous SiC. PHYSICAL REVIEW LETTERS 2004; 92:015502. [PMID: 14753997 DOI: 10.1103/physrevlett.92.015502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2003] [Revised: 09/16/2003] [Indexed: 05/24/2023]
Abstract
We report the observation of a paramagnetic interface defect in thermally oxidized porous n-type doped 4H-SiC/SiO(2). Based on its axial symmetry and resolved hyperfine interactions it is attributed to an sp(3) carbon dangling bond center situated at the SiC side of the interface. This center is electrically active and pins the Fermi level in the oxidized samples. No silicon related paramagnetic dangling bond centers are observed. The formation of dangling bond centers seems to be related to interstitial oxygen diffusion at the interface during the oxidation process.
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Affiliation(s)
- J L Cantin
- Groupe de Physique des Solides, Universités Paris 6&7, UMR 7588 au CNRS, 2, place Jussieu, 75005 Paris, France
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14
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Yamasaki T, Kato K, Uda T. Oxidation of the Si(001) surface: lateral growth and formation of P(b0) centers. PHYSICAL REVIEW LETTERS 2003; 91:146102. [PMID: 14611539 DOI: 10.1103/physrevlett.91.146102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2003] [Indexed: 05/24/2023]
Abstract
More than 100 oxygen-adsorbed configurations with oxygen coverage of up to two monolayers (ML) were studied through first-principles calculations. It was found that oxidation proceeds almost laterally. When the coverage exceeds 1.25 ML, oxygen atoms introduced between the second and third layers are captured at a bridging site in the second layer, generating twofold-coordinated Si atoms. Emission of such twofold-coordinated Si atoms leaves weakly bonded Si pairs in the fourth layer. When such pairs happen to be generated close to each other, they transform into a chain of Si trimers with one P(b0) center at each end.
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Affiliation(s)
- Takahiro Yamasaki
- Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi 243-0197, Japan.
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15
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Bongiorno A, Pasquarello A, Hybertsen MS, Feldman LC. Transition structure at the Si(100)-SiO2 interface. PHYSICAL REVIEW LETTERS 2003; 90:186101. [PMID: 12786026 DOI: 10.1103/physrevlett.90.186101] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2002] [Indexed: 05/24/2023]
Abstract
We characterize the transition structure at the Si(100)-SiO2 interface by addressing the inverse ion-scattering problem. We achieve sensitivity to Si displacements at the interface by carrying out ion-scattering measurements in the channeling geometry for varying ion energies. To interpret our experimental results, we generate realistic atomic-scale models using a first-principles approach and carry out ion-scattering simulations based on classical interatomic potentials. Silicon displacements larger than 0.09 A are found to propagate for three layers into the Si substrate, ruling out a transition structure with regularly ordered O bridges, as recently proposed.
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Affiliation(s)
- Angelo Bongiorno
- Institut de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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