Structural relaxation of SiO2/Si interfacial layer during annealing

Awaji, N.; Ohkubo, Satoshi; Nakanishi, Takafumi; Takasaki, Kanetake; Komiya, Satoshi

doi:10.1016/s0169-4332(97)80083-9

Cited by 13 publications

(10 citation statements)

References 9 publications

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“…The mean value is, however, not far from the experimental value (2.43 g/cm 3 ) measured for the planar oxide film. 16) Although further detailed investigation is required, the present simulation results are reasonable with respect to Si interface is about 2.1-2.7 g/cm 3 . many aspects compared with previous reports.…”

Section: Simulation Methodssupporting

confidence: 53%

Strain Distribution around SiO₂/Si Interface in Si Nanowires: A Molecular Dynamics Study

Ohta¹,

Watanabe

Ohdomari

2007

jjap

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We have performed three-dimensional molecular dynamics simulations to investigate strain and stress distributions in silicon nanostructures covered with thermal oxide films, by using our original molecular force field for Si, O mixed systems. We have modeled a wire-shaped nanostructure by carving a Si(001) substrate, and then an oxide film with a uniform thickness was formed by inserting oxygen atom into Si-Si bonds from the surface. The simulation results show that a compressive stress is concentrated on the oxide region in the vicinity of the side SiO 2 /Si interface of the nanowire. At the top interface, there is also a compressive stress in the [110] direction, whereas the [001] component of the normal stress tensor is almost relaxed. These results suggest that the oxidation is strongly suppressed at the side faces of the silicon nanowire.

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Section: Simulation Methodssupporting

confidence: 53%

Strain Distribution around SiO₂/Si Interface in Si Nanowires: A Molecular Dynamics Study

Ohta¹,

Watanabe

Ohdomari

2007

jjap

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“…These results are in accordance with studies performed directly on Si-SiO 2 interfaces. For example, suboxide bonding at Si-SiO 2 interfaces before and after annealing at 900°C has been studied by XPS, 7,30,31 AES, 13 TEM, 5 difference x-ray diffraction, 10 and more recently XPS using monochromatic synchrotron radiation. 4 These studies have confirmed the reduction of excess suboxide bonding by annealing in an inert ambient at 900°C.…”

Section: Discussionmentioning

confidence: 99%

“…4 Analysis of interface bonding chemistry and structure has shown that the improvements after annealing derive from reductions of suboxide bonding groups in interfacial transition regions, effectively smoothing the Si-SiO 2 interface. [4][5][6][7][8][9][10][11][12][13] Studies of SiC-SiO 2 interfaces have also identified an interfacial compositional transition layer. [14][15][16] Depending on the substrate polytype, oxidation temperature, and ambient ͑wet versus dry͒, results have shown that carbon atoms may become trapped in the growing oxide as they outdiffuse from the interface, forming an oxycarbide interface layer.…”

Section: Introductionmentioning

confidence: 99%

Thermochemical stability of silicon–oxygen–carbon alloy thin films: A model system for chemical and structural relaxation at SiC–SiO2 interfaces

Wolfe¹,

Hinds²,

Wang³

et al. 1999

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Alloy thin films of hydrogenated silicon-oxygen-carbon ͑Si,C͒O x xϽ2, were deposited and analyzed in terms of changes in structure and bonding as a function of rapid thermal annealing between 600 and 1100°C using a combination of Fourier transform infrared spectroscopy, Raman scattering and high-resolution transmission electron microscopy. Results showed that three structural/chemical transformations took place upon annealing. The initial reaction ͑600-800°C͒ involved the loss of hydrogen bonded to both silicon and carbon. At intermediate temperatures ͑900-1000°C͒ a Si-O-C type bond was observed to form, and subsequently disappear after annealing to 1050°C. The formation of ordered amorphous-SiC regions, nanocrystalline-Si regions, and stoichiometric, thermally relaxed SiO 2 accompanied the disappearance of the Si-O-C bond at the 1050°C annealing temperature. Using this alloy as a model system, important information is obtained for optimized processing of SiC-SiO 2 interfaces for device applications.

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“…The SiO 2 films had densities of 2.25-2.27 g/cm 3 that was constant for the depth direction, except where the high-density layer of approximately 2.3 g/cm 3 existed at the interface. 19,20 The observed densities were higher than that of amorphous of 2.2 g/cm 3 . From the results, formation of crystalline structure may influence density.…”

mentioning

confidence: 74%

Structural Analyses of Thin SiO₂Films Formed by Thermal Oxidation of Atomically Flat Si Surface by Using Synchrotron Radiation X-Ray Characterization

Nagata

Ogura

Hirosawa

et al. 2015

ECS J. Solid State Sci. Technol.

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Partially crystalline structures in thin SiO 2 films formed by thermal oxidation of atomically flat Si surface were investigated by performing X-ray reflectometry and grazing incidence X-ray diffraction measurements. The densities of the SiO 2 films were higher than those of amorphous SiO 2 films, especially at the SiO 2 /Si interface. The structure of thermally grown SiO 2 has been expected to be amorphous, but sharp diffraction peaks were observed in GIXRD measurements. The diffraction peaks tended to reflect a cristobalite-like structure with preferential orientations to the Si substrate. In addition, the lattice spacing of the cristobalite-like structure was estimated from the GIXRD measurement and found to be isotropically distorted. Silicon dioxide (SiO 2 ) thin films of less than 10 nm are among the important dielectric materials for semiconductor devices, and many research studies on this material are actively being performed. [1][2][3][4][5][6] It is necessary to understand the formation process of the oxidation film to get high quality insulation characteristic. Thin SiO 2 films provide excellent electrical insulation and interface state densities, and they can readily be obtained using thermal oxidation. Generally, thermally grown SiO 2 film has an amorphous structure based on six-membered rings consisting of Si-O triangular pyramids. However, it was also reported that relatively thick SiO 2 film has a residual ordered structure reflecting the crystalline structure of the Si substrate.7-11 However, the detailed structure of the SiO 2 film has not been sufficiently revealed by these studies yet. In particular, the evaluation of thin SiO 2 films of less than 10 nm is very difficult because of the small scattering volume and the probably low degree of order in the structure. In this study, X-ray reflectometry (XRR) and grazing incident-angle X-ray diffraction (GIXRD) using synchrotron radiation were performed to evaluate the structures of thin SiO 2 films on the atomically flat surface. ExperimentalThin SiO 2 films were fabricated on the Si (001) substrate after the atomic-order planarization process consisting of thermal annealing at 1200• C for 30 min in a pure Ar atmosphere. 12-14 The Si surface thus had monoatomic steps with a height of 0.136 nm and atomically flat terraces with a width of approximately 150 nm. The surface roughness in each terrace was 0.03 nm; it was less than the detection limit of atomic force microscopy. Then, thermal oxidation was carried out in a pure oxygen atmosphere with three different temperatures. We prepared a SiO 2 sample grown with an 800• C process for 82 min, with a 900• C process for 13 min and with an 1100• C process for 30 sec. These thicknesses of SiO 2 films were approximately 7 nm. The purities of used oxygen gas were 99.9995%. GIXRD measurements were performed at SPring-8 BL46XU (2012A1597) using synchrotron radiation with a photon energy of 10 keV. The penetration depth of the X-rays into the sample varied rapidly near the critical angle. 15,16 The grazing an...

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Structural relaxation of SiO2/Si interfacial layer during annealing

Cited by 13 publications

References 9 publications

Strain Distribution around SiO₂/Si Interface in Si Nanowires: A Molecular Dynamics Study

Strain Distribution around SiO₂/Si Interface in Si Nanowires: A Molecular Dynamics Study

Thermochemical stability of silicon–oxygen–carbon alloy thin films: A model system for chemical and structural relaxation at SiC–SiO2 interfaces

Structural Analyses of Thin SiO₂Films Formed by Thermal Oxidation of Atomically Flat Si Surface by Using Synchrotron Radiation X-Ray Characterization

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Structural relaxation of SiO2/Si interfacial layer during annealing

Cited by 13 publications

References 9 publications

Strain Distribution around SiO2/Si Interface in Si Nanowires: A Molecular Dynamics Study

Strain Distribution around SiO2/Si Interface in Si Nanowires: A Molecular Dynamics Study

Thermochemical stability of silicon–oxygen–carbon alloy thin films: A model system for chemical and structural relaxation at SiC–SiO2 interfaces

Structural Analyses of Thin SiO2Films Formed by Thermal Oxidation of Atomically Flat Si Surface by Using Synchrotron Radiation X-Ray Characterization

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Strain Distribution around SiO₂/Si Interface in Si Nanowires: A Molecular Dynamics Study

Strain Distribution around SiO₂/Si Interface in Si Nanowires: A Molecular Dynamics Study

Structural Analyses of Thin SiO₂Films Formed by Thermal Oxidation of Atomically Flat Si Surface by Using Synchrotron Radiation X-Ray Characterization