Статті в журналах: "TZM - SiC"

1

Portelli, Marcus, Alessandro Bertarelli, Federico Carra, Michele Pasquali, Nicholas Sammut, and Pierluigi Mollicone. "Numerical and experimental benchmarking of the dynamic response of SiC and TZM specimens in the MultiMat experiment." Mechanics of Materials 138 (November 2019): 103169. http://dx.doi.org/10.1016/j.mechmat.2019.103169.

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2

Nikzad Khangholi, Siamak, Mousa Javidani, Alexandre Maltais, and X. Grant Chen. "Investigation on electrical conductivity and hardness of 6xxx aluminum conductor alloys with different Si levels." MATEC Web of Conferences 326 (2020): 08002. http://dx.doi.org/10.1051/matecconf/202032608002.

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The impact of Si levels on electrical conductivity (EC) and hardness in Al-Mg-Si 6xxx aluminum conductor alloys was studied at different aging times. Three experimental alloys with the Si levels of 0.4, 0.66, 0.89 wt.% containing a constant Mg content of 0.65 wt.%, designated as Si4, Si6, and Si9, were selected. It is found that the average peak hardness of Si4, Si6, and Si9 alloys were 114, 127 and 140 HV, respectively. The Si9 alloy with the highest Si level exhibited the highest peak hardness, which was consistent with the number density of strengthening precipitates. However, the EC of all studied alloys at peak aging was lower than the minimum required one (52.5 %IACS). The higher Si level in the alloy, the longer aging time required to enhance EC. The Si4, Si6, and Si9 alloys reached the minimum required EC after 3, 5 and 34 h aging time, of which the corresponding hardness was 103, 119 and 111 HV, respectively. Consequently, the Si6 alloy represented a better trade-off between EC and hardness among three studied alloys. The quantitative analyses of precipitates at peak aging and overaging states were carried out by a transmission electron microscope (TEM) investigation.

3

Liu, R. J., L. M. Porter, M. J. Kim, R. W. Carpenter, and R. F. Davis. "Microstructure of Cr-B Ohmic and Rectifying Contacts on (0001) 6H Sic." Microscopy and Microanalysis 3, S2 (August 1997): 641–42. http://dx.doi.org/10.1017/s1431927600038484.

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6H-SiC is a wide band-gap semiconductor. In recent years, a variety of high-power, -temperature, -speed and opto-electronic devices have been produced in 6H-SiC films. The future development of SiC device technology depends on the ability to form good ohmic and Schottky contacts. Plots of the current-voltage (I-V) characteristics of Cr-B contacts on (0001) 6H-SiC revealed that they became the most ohmic-like after annealing at 1000 °C for 240 sec. and rectifying after annealing for 300 sec, therefore TEM analysis of the microstructures of as-deposited and annealed Cr-B films should help in understanding what causes both the ohmic-like and rectifying behaviors.In this research, CrxBy film was deposited on vicinal (0001) 6H-SiC substrates by electron beam evaporation at room temperature. The intended phase was CrB2. Fig.l shows the microstructure of the as-deposited specimen. 6H-SiC appears to be a perfect crystal, but the Cr-B film had columnar polycrystalline microstructure.

4

Liu, R. J., L. M. Porter, M. J. Kim, R. W. Carpenter, and R. F. Davis. "Microstructure of Cr-B Ohmic and Rectifying Contacts on (0001) 6H Sic." Microscopy and Microanalysis 3, S2 (August 1997): 641–42. http://dx.doi.org/10.1017/s1431927600010096.

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6H-SiC is a wide band-gap semiconductor. In recent years, a variety of high-power, -temperature, -speed and opto-electronic devices have been produced in 6H-SiC films. The future development of SiC device technology depends on the ability to form good ohmic and Schottky contacts. Plots of the current-voltage (I-V) characteristics of Cr-B contacts on (0001) 6H-SiC revealed that they became the most ohmic-like after annealing at 1000 °C for 240 sec. and rectifying after annealing for 300 sec, therefore TEM analysis of the microstructures of as-deposited and annealed Cr-B films should help in understanding what causes both the ohmic-like and rectifying behaviors.In this research, CrxBy film was deposited on vicinal (0001) 6H-SiC substrates by electron beam evaporation at room temperature. The intended phase was CrB2. Fig.l shows the microstructure of the as-deposited specimen. 6H-SiC appears to be a perfect crystal, but the Cr-B film had columnar polycrystalline microstructure.

5

Park, K., and C. Sung. "Characterization of SiC fiber-reinforced SiC composites by TEM." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 632–33. http://dx.doi.org/10.1017/s042482010017089x.

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SiC fiber-reinforced SiC composites have been accepted to have considerable potential as an engineering structural ceramic for numerous high-temperature applications, such as various heat engine components. In this study, the microstructure of matrix, fiber, and matrix/fiber interface of SiC fiber (SCS-6, Textron)-reinforced nitrogen-treated SiC composites was characterized using transmission electron microscopy (TEM). Cross-sectional TEM samples were prepared by mechanical grinding, dimpling, and ion-milling. The samples were analyzed using a Philips EM400T TEM and a Noran ultrathin window Micro-Z detector.The α-Si3N4 was formed in the porous SiC matrix by nitriding (Fig. 1(a)). The porous SiC matrix can permit easy and continuous penetration of the nitriding gas and rapid escape of the reaction and volatilization products, thus favoring vapor-phase reactions. In the case of huge SiC grains, the α-Si3N4 was formed at the surface of the huge SiC grains. Rod-shaped Si2N2O phase was often observed in the porous matrix. Figs. 1(b), (c), and (d) show electron diffraction patterns obtained from the α-SiC, α-Si3N4, Si2N2O phases, respectively.

6

Aoki, Masahiko, Megumi Miyazaki, Taro Nishiguchi, Hiroyuki Kinoshita, and Masahiro Yoshimoto. "TEM Observation of the Polytype Transformation of Bulk SiC Ingot." Materials Science Forum 600-603 (September 2008): 365–68. http://dx.doi.org/10.4028/www.scientific.net/msf.600-603.365.

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This article describes the analysis of the polytype transformation of SiC ingot. We analyzed the sample by Raman spectroscopy and TEM observation. The result of the analysis shows the polytype is transformed from 4H-SiC to 6H-SiC, and then returned to 4H-SiC. We found that the direction of the c-axis is not the same as the growth direction of the ingot. And also we found the existence of 8H-SiC at the interface between 6H-SiC and 4H-SiC region by the selected area diffraction pattern and confirmed it by HR-TEM observation.

7

Wang, E. Y., X. Pan, J. P. Mansfield, T. Kennedy, and S. Hampshire. "TEM Studies of Silicon Nitride-Silicon Carbide Nanocomposites." Microscopy and Microanalysis 3, S2 (August 1997): 411–12. http://dx.doi.org/10.1017/s1431927600008941.

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Si3N4/SiC nanocomposites have been shown to exhibit excellent strength and fracture toughness compared to monolithic Si3N4 materials. Recently, the microstructure and chemistry of Si3N4-based nanocomposites fabricated by hot-pressing amorphous Si-C-N precursor powders has been investigated. In the present work, our studies on the microstructure of Si3N4/SiC nanocomposites made by hot-pressing the mixture of Si3N4 and SiC commercial powders are reported.Si3N4/SiC nanocomposites were prepared by hot-pressing at 1750 °C for 1 hour at 40 Mpa in a nitrogen atmosphere, with sintering aids of 5.5 wt% Y2O3 and 3 wt% Al2O3. The details of the processing procedure have been reported elsewhere. Two different materials were investigated in this work: specimen A consisting of 5 vol% β-SiC; and specimen B consisting of 5 vol% α-SiC. TEM specimens were prepared by conventional procedures. The microstructure and chemical composition were studied in the University of Michigan Electron Microbeam Analysis Laboratory on a JEOL 2000FX.

8

Bertrand, S., C. Droillard, R. Pailler, X. Bourrat, and R. Naslain. "TEM structure of (PyC/SiC)n multilayered interphases in SiC/SiC composites." Journal of the European Ceramic Society 20, no. 1 (January 2000): 1–13. http://dx.doi.org/10.1016/s0955-2219(99)00086-2.

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9

Diot, C., and V. Arnault. "Orientation Anisotropy in SiC Matrix of Unidirectional SiC/SiC Composite." Textures and Microstructures 14 (1991): 389–95. http://dx.doi.org/10.1155/tsm.14-18.389.

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10

Nutt, S. R., та David J. Smith. "High-resolution TEM of thin-film β-SiC interfaces". Proceedings, annual meeting, Electron Microscopy Society of America 44 (серпень 1986): 408–9. http://dx.doi.org/10.1017/s0424820100143638.

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Silicon carbide is a large band gap semiconductor under development for microelectronic device applications involving high temperatures, high frequencies, and high power. Single crystal thin films of high purity β-SiC can be fabricated by epitaxial CVD onto a <100> silicon wafer substrate. Epitaxial growth is achieved by a two-step process in which the surface of the silicon substrate is first converted to SiC by heating in the presence of hydrocarbon vapors, Despite the large lattice mismatch, this process results in an epitaxial film of β-SiC 10nm in thickness, upon which the SiC crystal is then chemically vapor deposited. Relatively thick (20 microns) crack-free films of SiC can thus be fabricated, although significant problems remain, such as lattice constant and thermal expansivity mismatches, and metallization and passivation of the surface. These reasons have provided the motivation for a detailed examination of interface structures in β-SiC thin films using HRTEM imaging of cross-sectional specimens.

11

Carter, C. H., J. E. Lane, J. Bentley, and R. F. Davis. "Determination of creep mechanisms in various silicon carbides via TEM." Proceedings, annual meeting, Electron Microscopy Society of America 44 (August 1986): 484–87. http://dx.doi.org/10.1017/s0424820100143973.

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Silicon carbide (SiC) is the generic name for a material which is produced and fabricated by a number of processing routes. One of the three SiC materials investigated at NCSU is Norton Company's NC-430, which is produced by reaction-bonding of Si vapor with a porous SiC host which also contains free C. The Si combines with the free C to form additional SiC and a second phase of free Si. Chemical vapor deposition (CVD) of CH3SiCI3 onto a graphite substrate was employed to produce the second SiC investigated. This process yielded a theoretically dense polycrystalline material with highly oriented grains. The third SiC was a pressureless sintered material (SOHIO Hexoloy) which contains B and excess C as sintering additives. These materials are candidates for applications such as components for gas turbine, adiabatic diesel and sterling engines, recouperators and heat exchangers.

12

Matsuhata, Hirofumi, Junji Senzaki, Ichiro Nagai, and Hirotaka Yamaguchi. "TEM Observation of SiO₂/4H-SiC Hetero Interface." Materials Science Forum 600-603 (September 2008): 671–74. http://dx.doi.org/10.4028/www.scientific.net/msf.600-603.671.

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The SiO2/4H-SiC hetero-interface was observed using TEM in plan-view geometry. Local roughening of the SiO2/4H-SiC hetero-interface accompanied with local generation of basal-plane dislocations in SiC was observed. In some places, local variations in film thickness of SiO2 as well as the presence of extra carbon and particle-like contrast asociated with the generation of basal-plane dislocations in SiC was observed. The influence of these defect regions on MOSFET properties is discussed.

13

Liu, R. J., M. J. Kim, R. W. Carpenter, L. M. Porter, L. P. Scheunemann, and R. F. Davis. "A TEM Study of Cr Based Contacts to (0001) 6H-SiC." Microscopy and Microanalysis 6, S2 (August 2000): 1064–65. http://dx.doi.org/10.1017/s1431927600037818.

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6H-SiC is a wide band-gap semiconductor. In recent years, a variety of high-power, -temperature, -speed and optoelectronic devices have been produced in SiC films. The search for metals which can form thermally stable, uniform ohmic contacts with SiC with low resistivity is still ongoing. In this study, Cr and CrBx (1<x<2) films were deposited by electron beam evaporation onto p-type, vicinal Si-terminated (0001) 6H-SiC surface. Both contacts exhibited rectifying behavior in the as-deposited condition. Ohmic-like behavior was observed for Cr/SiC system after annealing at 1000 °C for 240 seconds in a rapid thermal anneal furnace in an Ar atmosphere. It was also reported that ohmic behavior was observed for CrB2 /SiC system after annealing at 1100 °C for 2 minutes at a pressure of 5x10“7 Torr.2 The microstructure and chemistry of these two contact systems in both as-deposited and annealed conditions were investigated by transmission electron microscopy (TEM).

14

Marinova, Maya, Alkyoni Mantzari, Milena Beshkova, Mikael Syväjärvi, Rositza Yakimova, and Efstathios K. Polychroniadis. "TEM Investigation of the 3C/6H-SiC Transformation Interface in Layers Grown by Sublimation Epitaxy." Solid State Phenomena 163 (June 2010): 97–100. http://dx.doi.org/10.4028/www.scientific.net/ssp.163.97.

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In the present work Conventional and High Resolution Transmission Electron Microscopy has been used to examine the structure and types of interfaces between 3C-SiC and 6H-SiC for samples grown by Sublimation Epitaxy. The layers were grown on on-axis 6H-SiC substrates at different temperature gradients. The changed growth conditions influence on the nucleation of 3C-SiC on the 6H-SiC substrates and their competition with nucleation of 6H-SiC islands. Three specific types of 3C/6H-SiC interfaces were observed and the implications of these observations are discussed.

15

Perić Gavrančić, Sanja. "Sic etiam Croati." Povijesni prilozi 39, no. 58 (2020): 7–28. http://dx.doi.org/10.22586/pp.v39i58.10115.

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U radu se donose rezultati istraživanja latinskih povijesnojezičnih izvora koji otkrivaju što su o jeziku i pismu Hrvata znali europski renesansni humanisti prije nego što su prvi pokušaji kodifikacije hrvatskoga jezika u povijesnome i ideološkome kontekstu katoličke obnove osigurali njegovo službeno uključivanje u jezični zemljovid Europe. Šesnaestostoljetna je res publica litteraria, zahvaljujući intenzivnim humanističkim kontaktima i vezama, između ostalih tema omogućila i širenje ideje humanističkoga ilirizma koji je uključivao i pitanje jezika slavenskih naroda, pa tako i hrvatskoga. Sudionici te ranonovovjekovne zajednice intelektualaca razmjenjivali su, i u svojim raspravama diljem Europe objavljivali, podatke o hrvatskome jeziku i pismu. Takve su bilješke potvrđene u djelima francuskoga lingvista Guillauma Postela (Linguarum duodecim characteribus differentium alphabetum, 1538., Pariz) te švicarskih filologa Theodora Bibliandera (De ratione communi omnium linguarum et litterarum commentarius, 1548., Zürich) i Conrada Gesnera (Mithridates sive de differentiis linguarum tum veterum tum quae hodie apud diversas nationes in toto orbe terrarum in usu sunt, 1555., Zürich). U humanističkim je početcima kontrastivne lingvistike sudjelovao i jedan hrvatski latinist. Riječ je o Bartolu Đurđeviću i njegovu djelu o nevoljama kršćanskih zarobljenika pod turskom vlašću (De afflictione tam captivorum quam etiam sub Turcae tributo viventium Christianorum, 1544., Antverpen). Đurđević je prikazao razlike između hrvatskoga i turskoga jezika, objavio mali hrvatsko-latinski rječnik i tekst Očenaša, koji je kao ogledni tekst ilirskoga jezika citiran u spomenutome Biblianderovu i Gesnerovu repertoriju svjetskih jezika.

16

Borysiuk, Jolanta, Wlodek Strupiński, Rafał Bożek, Andrzej Wysmolek, and Jacek M. Baranowski. "TEM Investigations of Graphene on 4H-SiC(0001)." Materials Science Forum 615-617 (March 2009): 207–10. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.207.

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Transmission Electron Microscopy (TEM) investigations of graphene layers on Si terminated 4H-SiC(0001) are presented. The graphene layers have been grown in a standard method using decomposition of silicon carbide. Two kind of graphene layers have been investigated: 1) grown on substrates with on-axis orientation, 2) grown on substrates with 4° and 8° off-axis orientation in respect of c-axis of SiC. In the case of 0° orientation the high resolution TEM micrographs revealed that a thin layer graphene is present: 1-3 monolayers were obtained. It was found that the first carbon layer was about 2Å from the SiC surface. This result indicates that a strong covalent bonds between carbon layer and silicon atoms on the SiC surface exist. The subsequent graphene layers have been found spaced by 3.4 Å - similar as in the graphite. That indicates a weak van der Waals bonding between subsequent carbon layers. In the case of 4° and 8° off-axis orientation a thicker layer of about 5-6 monolayers of graphene were obtained. Relative spacings of graphene layers were the same as in the case of on-axis orientation.

17

Plummer, H. K., S. E. Shinozaki, B. N. Juterbock, and R. M. Williams. "TEM Observation of a Mechanically Thinned SiC Material." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 232–33. http://dx.doi.org/10.1017/s0424820100118084.

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When SiC materials are sintered or heat-treated at 2100°C or higher, abnormal morphological development occurs, due to exaggerated grain growth, decomposition of SiC and of second phase zones. A detailed study of the graphite and other second phase formations is important to correlate the microstructure to mechanical properties of SiC materials at high temperature. Large graphite formations have been observed with SEM and optically, but confirmation of these second phase formations has been hindered due to preferential etching of these regions using normal ion beam thinning techniques. In addition, once a small hole is formed in the second phase regions, the hole is quickly blunted by the ion beam. In this study mechanical thinning equipment designed and built by us(2) has been used to prepare electron transparent specimens for TEM analysis.

18

Gkanatsiou, Alexandra, Christos B. Lioutas, Nikolaos Frangis, Narendraraj Chandraraj, Efstathios K. Polychroniadis, Pawel Prystawko, and Mike Leszczynski. "TEM Study of AlGaN/GaN on Hexagonal SiC Substrates." Advanced Materials Research 936 (June 2014): 656–60. http://dx.doi.org/10.4028/www.scientific.net/amr.936.656.

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The present work concerns the microstructural characterization of a multi-component (based on GaN and related materials) and multi-layered (5 layers) film, grown on 6H-SiC substrate (with a misorientation of 1 degree off from the (0001) plane), using transmission electron microscopy (TEM). The TEM characterization showed no surface undulation, despite the presence of steps in the SiC/AlN interface.

19

Marinova, Maya, Georgios Zoulis, Teddy Robert, Frédéric Mercier, Alkyoni Mantzari, Irina G. Galben-Sandulache, Olivier Kim-Hak, et al. "TEM and LTPL Investigations of 3C-SiC Layers Grown by LPE on (100) and (111) 3C-SiC Seeds." Materials Science Forum 645-648 (April 2010): 383–86. http://dx.doi.org/10.4028/www.scientific.net/msf.645-648.383.

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In the present work the defects appearing in layers grown by liquid phase epitaxy on different substrates are compared. The used seeds were (i) 3C-SiC with (111) orientation, grown heteroepitaxially on (0001) 4H-SiC or 6H-SiC substrates by continuous feed physical vapour transport process and the vapour-liquid-solid mechanism, respectively, and (ii) 3C-SiC wafer with (100) orientation from HOYA. The structural and optical investigation showed that (i) on the (111) substrates, due to the appearance of silicon and 6H-SiC inclusions, a layer which consisted of a sequence of long period polytypes was formed. The dominant polytype formed was 21R-SiC, which after successive transformation to 39R- and 57R- SiC led to the formation of 6H-SiC on the top of the layer. (ii) On the (100) substrates, a 3C-SiC layer with comparatively uniform defect density was formed. The main defects were stacking faults and their density was reducing during the process.

20

Kameda, Toshimasa, Atsuo Tomita, Takaaki Matsui, and Toshiyuki Isshiki. "TEM Observation of Defect Structure of Low-Energy Ion Implanted SiC." Materials Science Forum 778-780 (February 2014): 350–53. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.350.

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The aim of this review is to present the observation of low-energy ion implanted SiC and annealing them by using TEM. By detail analyses of the TEM images and results of SRIM, ion implanted SiC was classification four structure depending on the ion concentration in a few ten nm shallow region. This results suggest that crystal structure in a few nm shallow region can be controled by concentration of the ion implant. And SiC was re-crystallized single poly-type after annealed at 1500°C. But, defects in end of amorphous region affect to recover the damaged structure .

21

Elizalde, M. R., E. Paris, and J. Gil-Sevillano. "La intercara fibra-matriz de un compuesto CMC de SiC-SiC: Comparación de imágenes SEM, TEM y AFM." Revista de Metalurgia 34, Extra (May 30, 1998): 226–31. http://dx.doi.org/10.3989/revmetalm.1998.v34.iextra.743.

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22

Swiderska-Sroda, Anna, J. A. Kozubowski, A. Maranda-Niedbala, Ewa Grzanka, Bogdan F. Palosz, A. Presz, Stanislaw Gierlotka, et al. "Investigation of the Microstructure of SiC-Zn Nanocomposites by Microscopic Methods: SEM, AFM and TEM." Solid State Phenomena 101-102 (January 2005): 151–56. http://dx.doi.org/10.4028/www.scientific.net/ssp.101-102.151.

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SiC-Zn nanocomposites with about 20% volume fraction of metal were fabricated by infiltration process under the pressure of 2-8 GPa and at the temperature of 400_1000oC. SiC nanopowders used in the experiments formed loosely agglomerated chains of single crystal nanoparticles. The dimension of the agglomerates was in the micrometer range, the mean grain size was up to tens of nanometers. Microstructural investigations of the nanocomposites were performed at a different resolution levels using scanning, transmission electron microscopy and atomic force microscopy techniques (SEM, TEM, AFM, respectively). SEM observations indicate a presence of nano-dispersed, uniform (on the micrometer scale) mixture of two phases. TEM observations show that distribution of SiC and Zn nanocrystallites is uniform on the nanometer scale. High-resolution TEM images demonstrate an existence of thin (on the order of tens of Angstroms) Zn layers separating SiC grains. AFM images of the mechanically polished samples show a smooth surface with the roughness on the order of the SiC grain size (10-30 nm). After ion etching of some samples the AFM topographs show surface irregularities: periodically spaced hillocks 50-100 nm in height. The size of the SiC grains remains equal to that of the initial powder crystallites. The size of the Zn grains varies in the range of 20-100 nm depending on the initial SiC grain size and the composite fabrication conditions.

23

Rossi, Francesca, Filippo Fabbri, Giovanni Attolini, Matteo Bosi, Bernard Enrico Watts, and Giancarlo Salviati. "TEM and SEM-CL Studies of SiC Nanowires." Materials Science Forum 645-648 (April 2010): 387–90. http://dx.doi.org/10.4028/www.scientific.net/msf.645-648.387.

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-SiC and -SiC/SiO2 core-shell nanowires (NWs) grown on silicon substrates by three different processes, based on the use of i) carbon monoxide, ii) silane with propane and iii) carbon tetrachloride precursors, are analysed by structural and optical techniques. Spectroscopic cathodoluminescence studies show a luminescence enhancement in core-shell structures, ascribed to an effective role of the shell as both carrier injecting barrier and passivation layer. In NWs grown using CCl4 precursor, a peculiar luminescence with dominant red component at about 2 eV has been detected and ascribed to point defects related to an unintentional oxygen incorporation.

24

Ruterana, P., B. Beaumont, P. Gibart, and Y. Melnik. "A TEM study of GaN grown by ELO on (0001) 6H-SiC." MRS Internet Journal of Nitride Semiconductor Research 5, S1 (2000): 76–82. http://dx.doi.org/10.1557/s1092578300004105.

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The misfit between GaN and 6H-SiC is 3.5 % instead of 16 % with sapphire, the epitaxial layers have similar densities of defects on both substrates. Moreover, the lattice mismatch between AlN and 6H-SiC is only 1%. Therefore, epitaxial layer overgrowth (ELO) of GaN on AlN/6H-SiC could be a route to further improve the quality of epitaxial layers. AlN has been grown by Halide Vapour Phase Epitaxy (HVPE) on (0001) 6H-SiC, thereafter a dielectric SiO2 mask was deposited and circular openings were made by standard photolithography and reactive ion etching. We have examined GaN layers at an early stage of coalescence in order to identify which dislocations bend and try to understand why. The analysed islands have always the same hexagonal shape, limited by facets. The a type dislocations are found to fold many times from basal to the prismatic plane, whereas when a+c dislocations bend to the basal plane, they were not seen to come back to a prismatic one.

25

Borysiuk, Jolanta, Rafał Bożek, Wlodek Strupiński, and Jacek M. Baranowski. "Graphene Growth on C and Si-Face of 4H-SiC – TEM and AFM Studies." Materials Science Forum 645-648 (April 2010): 577–80. http://dx.doi.org/10.4028/www.scientific.net/msf.645-648.577.

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Transmission Electron Microscopy (TEM) investigations of graphene layers synthesized on Si and C-terminated on-axis oriented 4H-SiC are presented. The high-resolution TEM (HRTEM) revealed distinctive distance differences between the first carbon graphene layer and SiC surface for both polarities. The prolonged annealing of SiC with carbon face shows, that in addition to the increase of number of graphene layers, there is also observed splitting between stack of graphene layers and the surface of SiC substrate. In addition, the density of so called “puckers” increases.

26

Liu, J. Q., M. Skowronski, P. G. Neudeck, and J. A. Powell. "TEM Observation on Single Defect in SiC." Microscopy and Microanalysis 8, S02 (August 2002): 1180–81. http://dx.doi.org/10.1017/s143192760210777x.

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27

Danishevskii, A. M., M. V. Zamoryanskaya, A. A. Sitnikova, V. B. Shuman, and A. A. Suvorova. "TEM and cathodoluminescence studies of porous SiC." Semiconductor Science and Technology 13, no. 10 (October 1, 1998): 1111–16. http://dx.doi.org/10.1088/0268-1242/13/10/010.

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28

Alani, R., and P. R. Swann. "TEM specimen preparation of individual SiC/C composite (SCS-6) fibers." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 1104–5. http://dx.doi.org/10.1017/s0424820100089834.

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SiC/C based fibers (SCS) have exciting possibilities as reinforcements in advanced metal and ceramic matrix composite materials and there has been a growing interest in preparing specimens of these fibers for TEM studies. Unfortunately, the task of preparing very thin cross section of entire fibers is difficult because the constituent materials making up the fibers have widely different ion milling rates i.e. a carbon core surrounded by a SiC layer coated internally and externally with carbon. In this article, a rapid and reliable technique for preparing TEM specimen of the SCS-6 SiC fiber (manufactured by Textron) is described and together with the results of CTEM, HREM and PEELS studies. The technique is based on a general method of TEM specimen preparation of small objects, e.g. fibers and powder, reported elsewhere.

29

Lee, B.-T., D.-K. Kim, C.-K. Moon, J. K. Kim, Y. H. Seo, K. S. Nahm, H. J. Lee, et al. "Microstructural investigation of low temperature chemical vapor deposited 3C-SiC/Si thin films using single-source precursors." Journal of Materials Research 14, no. 1 (January 1999): 24–28. http://dx.doi.org/10.1557/jmr.1999.0006.

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Transmission electron microscopy (TEM) was utilized to investigate microstructures of heteroepitaxial SiC/Si films, grown from single-source precursors such as tetramethylsilane [TMS, Si(CH3)4], hexamethyldisilane [HMDS, Si2(CH3)6], and 1,3-disilabutane [1,3-DSB, H3SiCH2SiH2CH3]. In the case of TMS/H2 and HMDS/H2 samples, SiC/Si films grown at relatively high precursor concentration and/or low temperatures showed columnar grains with a high degree of epitaxial relationship with the Si substrate. Higher quality films with larger grains were observed in the case of high temperature and/or low precursor concentration samples, although a high density of interfacial voids was observed. Samples grown from pure 1,3-DSB at a low pressure showed high quality single crystalline films with few interfacial voids. It was suggested that the microstructural behavior of these films closely resembles that of the SiC films formed during the carbonization of Si surfaces by the pyrolysis of hydrocarbons, in which the nucleation rate of the film at the initial stage plays a key role. The improvement achieved during the 1,3-DSB growth is proposed to be due to the low growth pressure and the 1 : 1 ratio of Si and C associated with this precursor.

30

Bow, J. S., F. Shaapur, M. J. Kim, and R. W. Carpenter. "Preparation of thin-film-metal/6H-SiC TEM specimens by RPR ion milling." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 714–15. http://dx.doi.org/10.1017/s0424820100149404.

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HRTEM has proven to be the best method to study the interface structure of heterogeneous materials at the atomic level. One of the critical steps in these experiments is preparation of sufficiently thin cross section TEM (XTEM) specimens with different materials on both sides of the interface in good condition for HRTEM, especially when metal/ceramic materials are of interest. For the material system of a thin metal film on 6H-SiC substrate, the conventional ion milling method did not produce satisfactory XTEM specimens, because of the large difference in ion milling rates between metals and SiC. Most of the metal was ion milled way before a thin area of SiC was obtained. Two very important parameters, the thickness of the metal thin film normal to the interface and the atomic bonding structure across the interface were usually lost. Fig.l shows an example. The original thickness of the metal was 100 nm, and most of that has been removed. An amorphous layer of 1 to 1.5 nm thickness apparently due to ion milling formed at the metal/SiC interface.

31

Mantzari, Alkyoni, Christos B. Lioutas, and Efstathios K. Polychroniadis. "A TEM Study of Inversion Domain Boundaries Annihilation Mechanism in 3C-SiC during Growth." Materials Science Forum 615-617 (March 2009): 331–34. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.331.

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The aim of the present work is to study the evolution and the annihilation of inversion domain boundaries in 3C-SiC during growth. For this investigation conventional and high resolution transmission electron microscopy were employed. It is shown that the physical mechanism which results in the annihilation of inversion domain boundaries in 3C-SiC starting from the 3C-SiC/Si interface is the change of the crystallographic planes in which inversion domain boundaries propagate into the {111} ones. In all cases modeling and simulation analysis by EMS software [1] are in agreement with the experimental results.

32

Yano, Toyohiko, Yoo Yamamoto, and K. Yoshida. "TEM Investigation and Fracture Behavior of SiC/SiC Composites Fabricated by Hot-Pressing." Key Engineering Materials 166 (April 1999): 135–38. http://dx.doi.org/10.4028/www.scientific.net/kem.166.135.

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33

Zhou, W. L., F. Namavar, P. C. Colter, M. Yoganathan, M. W. Leksono, and J. I. Pankove. "Characterization of GaN Grown on SiC on Si/SiO2/Si by Metalorganic Chemical Vapor Deposition." Journal of Materials Research 14, no. 4 (April 1999): 1171–74. http://dx.doi.org/10.1557/jmr.1999.0155.

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SiC (3C-SiC) was grown on the top Si layer of SIMOX (Si/SiO2/Si) by carbonization followed by chemical vapor deposition (CVD). Subsequently, GaN was deposited on the SiC by metalorganic (MO) CVD to produce a GaN/SiC/Si/SiO2/Si multilayer structure. This multilayer film was investigated by conventional transmission electron microscopy (TEM) and high-resolution (HR) TEM from cross-sectional view. The GaN layer was found to consist of predominately hexagonal gallium nitride (h-GaN), and a small fraction of cubic GaN (c-GaN) crystallites. The orientation relationship between most of the h-GaN grains and SiC (3C-SiC) was found to be (0001)Ga N||s(111)SiC; [1120]GaN||[110]SiC, while most of the c-GaN grains had an orientation relationship (001)GaN||(001)SiC; [110]GaN||[110]SiC with respect to 3C-SiC substrate. The hexagonal grains of GaN were found to grow as two variants. The defects in both h-GaN and c-GaN are also discussed.

34

Lebedev, Sergey P., Alexander A. Lebedev, Alla A. Sitnikova, Demid A. Kirilenko, Natasha V. Seredova, Alla S. Tregubova, and Mikhail P. Scheglov. "Heteroepitaxial Growth of 3C-SiC on Polar Faces of 6H-SiC Substrates, TEM Investigations." Materials Science Forum 740-742 (January 2013): 267–70. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.267.

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Abstract Results of an epitaxial growth of 3C-SiC epilayers on Si (0001) and C(000¯1) faces of hexagonal 6H-SiC substrates are described. TEM study of grown layers as well as interface between cubic and hexagonal polytypes is presented. Difference between the layers on the Si and C faces are discussed.

35

Giannuzzi, L. A., C. A. Lewinsohn, C. E. Bakis, and R. E. Tressler. "TEM of grain growth and phase transformations during creep of SCS-6 silicon carbide fibers." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 350–51. http://dx.doi.org/10.1017/s0424820100138129.

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The SCS-6 SiC fiber is a 142 μm diameter fiber consisting of four distinct regions of βSiC. These SiC regions vary in excess carbon content ranging from 10 a/o down to 5 a/o in the SiC1 through SiC3 region. The SiC4 region is stoichiometric. The SiC sub-grains in all regions grow radially outward from the carbon core of the fiber during the chemical vapor deposition processing of these fibers. In general, the sub-grain width changes from 50nm to 250nm while maintaining an aspect ratio of ~10:1 from the SiC1 through the SiC4 regions. In addition, the SiC shows a <110> texture, i.e., the {111} planes lie ±15° along the fiber axes. Previous has shown that the SCS-6 fiber (as well as the SCS-9 and the developmental SCS-50 μm fiber) undergoes primary creep (i.e., the creep rate constantly decreases as a function of time) throughout the lifetime of the creep test.

36

Cabibbo, Marcello. "Strengthening Evaluation in a Composite Mg-RE Alloy Using TEM." Materials Science Forum 678 (February 2011): 75–84. http://dx.doi.org/10.4028/www.scientific.net/msf.678.75.

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Magnesium alloys containing rare earth elements are known to have high specific strength and corrosion resistance. The addition of SiC ceramic particles makes the metal matrix composite stronger with better wear and creep resistance and a still good machinability. The role of the reinforcement particles to the enhanced strength can be quantitatively evaluated using transmission electron microscopy (TEM). This paper presents a quantitative strengthening evaluation in a SiC Mg-RE composite alloy. The different contributions were determined by TEM inspections. The microstructure strengthening mechanism was studied after room temperature compression specimens. The way of combining the different contributions and the comparison to the measured yield stress, is also discussed and justified.

37

Bow, J. S., M. J. Kim, and R. W. Carpenter. "Comparative Oxidation Studies of Polycrystalline HP and CVD Silicon Carbides by TEM." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 938–39. http://dx.doi.org/10.1017/s0424820100089007.

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The excellent oxidation resistance of SiC at high temperature results from formation of a protective SiO2 layer in a strongly oxidizing environment. The oxide layer is often initially amorphous, may transform to a crystalline phase for extended reaction time, especially crystobalite above 1200°C. Our objective is use of high resolution electron microscopy methods to determine the oxide layer microstructure dependence on SiC substrate type, and especially to investigate existence of an intermediate Si-O-C phase between the oxide layer and substrate.

38

Das, G., and R. E. Omlor. "TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 738–39. http://dx.doi.org/10.1017/s0424820100105758.

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Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

39

Burke, M. G., M. N. Gungor, and P. K. Liaw. "TEM examination of 2014-SiC metal matrix composite." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 726–27. http://dx.doi.org/10.1017/s0424820100105692.

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Aluminum-based metal matrix composites offer unique combinations of high specific strength and high stiffness. The improvement in strength and stiffness is related to the particulate reinforcement and the particular matrix alloy chosen. In this way, the metal matrix composite can be tailored for specific materials applications. The microstructural characterization of metal matrix composites is thus important in the development of these materials. In this study, the structure of a p/m 2014-SiC particulate metal matrix composite has been examined after extrusion and tensile deformation.Thin-foil specimens of the 2014-20 vol.% SiCp metal matrix composite were prepared by dimpling to approximately 35 μm prior to ion-milling using a Gatan Dual Ion Mill equipped with a cold stage. These samples were then examined in a Philips 400T TEM/STEM operated at 120 kV. Two material conditions were evaluated: after extrusion (80:1); and after tensile deformation at 250°C.

40

Olivier, E. J., та J. H. Neethling. "TEM analysis of planar defects in β-SiC". International Journal of Refractory Metals and Hard Materials 27, № 2 (березень 2009): 443–48. http://dx.doi.org/10.1016/j.ijrmhm.2008.09.013.

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41

Pirouz, P., and J. W. Yang. "Polytypic transformations in SiC: the role of TEM." Ultramicroscopy 51, no. 1-4 (June 1993): 189–214. http://dx.doi.org/10.1016/0304-3991(93)90146-o.

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42

Sitnikova, A. A., E. N. Mokhov, and E. I. Radovanova. "TEM Investigation of Radiation Defects in SiC Crystals." Physica Status Solidi (a) 135, no. 2 (February 16, 1993): K45—K49. http://dx.doi.org/10.1002/pssa.2211350232.

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43

More, K. L. "An investigation of ion beam and pulsed laser Ni-SiC mixed surface structures by cross-sectional TEM." Proceedings, annual meeting, Electron Microscopy Society of America 44 (August 1986): 512–13. http://dx.doi.org/10.1017/s0424820100144073.

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Ion beam and pulsed laser mixing have been used as surface modification techniques in an attempt to increase the mechanical properties of sintered α-SiC. Thin Ni overlayers (50 nm - 100 nm) were evaporated onto the SiC surface and subsequently irradiated with pulses of a krypton-fluoride (KrF) excimer laser or bombarded with high energy Si+ ions. Both techniques are non-equilibrium processing methods capable of inducing unique microstructural changes at the specimen surface which, under particular processing conditions, can result in enhanced physical properties. It has been shown previously that laser annealing of Ni-coated α-SiC resulted in a fracture strength increase of ≈20%; however, the fracture strength was not changed following ion beam mixing. High resolution cross-sectional transmission electron microscopy (X-TEM) was used to characterize the extent of mixing between the Ni and the SiC following surface modification.

44

YOON, HAN-KI, HO-JUN CHO, AKIRA KOHYAMA, and TETSUJI NODA. "R&D OF SICF/SIC COMPOSITE FOR FUSION REACTOR MATERIAL." International Journal of Modern Physics B 25, no. 31 (December 20, 2011): 4212–15. http://dx.doi.org/10.1142/s021797921106660x.

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During the operation of a fusion reactor, a certain type of transients could induce rapid cooldown of the reactor with relatively high or increasing system pressure. This induces a high tensile stress at the inner surface of the blanket, which is called the thermal shock. Test Blanket Module (TBM) has been designed to account for the performance of DEMO-relevant blanket. But, the TBM uses helium as coolant and tritium as purge gas, and FM steel, SiC f / SiC composites as a structural material. The SiC f / SiC composites with a SiC sub-layer/ PyC interlayers were therefore fabricated in order to improve the oxidation resistance. In the refractory field SiC f / SiC composites need to investigate residual stress and thermal shock behavior when high chemical stability and corrosion resistance are necessary. In this study, SiC f / SiC composite were fabricated by NITE process and the chemical vapor infiltration (CVI) method. SiC f / SiC composites have been examined and the detail analyses of the microstructure and the mechanical strength were conducted. Various pyrolytic carbons ( PyC ) with SiC interlayer coatings were applied to the composites for improvement of the mechanical properties at the interface.

45

Shibayama, T., H. Takahashi, M. Kawasaki, and A. Kohyama. "Interface structure analysis of SiC fibres reinforced SiC matrix composites by energy filtering TEM." Journal of Electron Microscopy 48, no. 6 (January 1, 1999): 893–97. http://dx.doi.org/10.1093/oxfordjournals.jmicro.a023762.

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46

Husnayani, Ihda, and Muzakkiy Putra Muhammad Akhir. "COLLISION CASCADE AND PRIMARY RADIATION DAMAGE IN SILICON CARBIDE: A MOLECULAR DYNAMICS STUDY." JURNAL TEKNOLOGI REAKTOR NUKLIR TRI DASA MEGA 24, no. 3 (November 9, 2022): 131. http://dx.doi.org/10.17146/tdm.2022.24.3.6702.

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Silicon carbide (SiC) is a competitive candidate material to be used in several advanced and Generation-IV nuclear reactor designs as neutron moderator, fuel coating, cladding, or core structural material. Many studies have been performed to investigate the durability of SiC in severe environment in nuclear reactor. However, the nature and behavior of defect induced by neutron irradiation are still not fully understood. This paper is aimed to study collision cascade and primary radiation damage in SiC using molecular dynamics simulation. The potential being used was a hybrid Tersoff potential modified with Ziegler-Biersack-Littmark (ZBL) screening function. The collision cascade was let evolved for 10 ps from a Si or C primary knocked atom (PKA) located initially at the top center of a system containing 960000 atoms. The simulation was carried out at room temperature as well as at several advanced fission reactor-relevant temperatures. It was obtained that the number of C point defects were larger than the number of Si point defects. The number of stable point defect was found to be temperature-dependent. It was also obtained that the recovery of point defects was larger at high temperature (>800°C).

47

Yasui, Kanji, T. Kurimoto, Masasuke Takata, and Tadashi Akahane. "SiCOI Structure Fabricated by Hot-Mesh Chemical Vapor Deposition." Advanced Materials Research 11-12 (February 2006): 257–60. http://dx.doi.org/10.4028/www.scientific.net/amr.11-12.257.

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The growth of 3C-SiC on thermal oxide layer of Si (SiO2) was investigated by hot-mesh (HM) chemical vapor deposition (CVD), which utilizes hot tungsten (W) wires of a mesh structure as a catalyzer. The SiC films were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and cross sectional transmission electron microscopy (TEM). From the XRD spectra of SiC films grown on SiO2 layer, (100) oriented SiC films were grown at the substrate temperatures of 750-800°C and the mesh temperature of 1600°C, while polycrystalline SiC films were grown at the substrate temperature above 900°C. From the data of FT-IR, TEM and the growth rate, the growth characteristics of SiC crystal by HMCVD were discussed.

48

Chien, F. R., S. R. Nutt, W. S. Yoo, T. Kimoto та H. Matsunami. "Terrace growth and polytype development in epitaxial β-SiC films on α-SiC (6H and 15R) substrates". Journal of Materials Research 9, № 4 (квітень 1994): 940–54. http://dx.doi.org/10.1557/jmr.1994.0940.

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Epitaxial β-SiC (3C) films were grown on (0001) 6H-SiC and 15R-SiC substrates by chemical vapor deposition (CVD). TEM characterization revealed that films on both substrates exhibited large areas of atomically flat, coherent interfaces. However, when 3C-SiC films were grown on 6H substrates, double position boundaries (DPB's) were frequently observed, and islands of 6H were occasionally embedded in the predominantly 3C film. In contrast, films of 3C-SiC grown on 15R substrates exhibited relatively few DPB's and only occasional islands of 15R. A model of interlay er interactions in SiC was applied to predict the atomic structures at both 3C/6H and 3C/s15R interfaces, and these predictions were consistent with experimental observations of the interfaces by TEM. The observed interface structures and defect distributions were attributed to a microscopic kinetic mechanism of terrace growth. Consideration of step energies and growth kinetics led to the prediction that DPB's can be avoided by growing 3C-SiC films on 15R-SiC substrates.

49

Fang, J., H. M. Chan, and M. P. Harmer. "TEM investigations of surface residual stress relaxation in A12O3 and Al2O3-SiC nanocomposite." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 628–29. http://dx.doi.org/10.1017/s0424820100170876.

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It was Niihara et al. who first discovered that the fracture strength of Al2O3 can be increased by incorporating as little as 5 vol.% of nano-size SiC particles (>1000 MPa), and that the strength would be improved further by a simple annealing procedure (>1500 MPa). This discovery has stimulated intense interest on Al2O3/SiC nanocomposites. Recent indentation studies by Fang et al. have shown that residual stress relief was more difficult in the nanocomposite than in pure Al2O3. In the present work, TEM was employed to investigate the microscopic mechanism(s) for the difference in the residual stress recovery in these two materials.Bulk samples of hot-pressed single phase Al2O3, and Al2O3 containing 5 vol.% 0.15 μm SiC particles were simultaneously polished with 15 μm diamond compound. Each sample was cut into two pieces, one of which was subsequently annealed at 1300° for 2 hours in flowing argon. Disks of 3 mm in diameter were cut from bulk samples.

50

Gokhman, Aleksandr R., Andreas Ulbricht, Uwe Birkenheuer, and Frank Bergner. "Cluster Dynamics Study of Neutron Irradiation Induced Defects in Fe-12.5at%Cr Alloy." Solid State Phenomena 172-174 (June 2011): 449–57. http://dx.doi.org/10.4028/www.scientific.net/ssp.172-174.449.

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Cluster dynamics (CD) is used to study the evolution of the size distributions of vacancy clusters (VC), self-interstitial atom (SIA) clusters(SIAC) and Cr precipitates in neutron irradiated Fe-12.5at%Cr alloys at T = 573 K with irradiation doses up to 12 dpa and a flux of 140 ndpa/s. Transmission electron microscopy (TEM) and small angle neutron scattering (SANS) data on the defect structure of this material irradiated at doses of 0.6 and 1.5 dpa are used to calibrate the model. A saturation behavior was found by CD for the free vacancy and free SIA concentrations as well as for the number density of the SIAC and the volume fraction of the Cr precipitates for neutron exposures above 0.006 dpa. The CD simulations also indicate the presence of VC with radii less than 0.5 nm and a strong SIAC peak with a mean diameter of about 0.5 nm, both invisible in SANS and TEM experiments. A specific surface tension of about 0.028 J/m2 between the a matrix and the Cr-rich a' precipitate was found as best fit value for reproducing the long-term Cr evolution in the irradiated Fe-12.5%Cr alloys observed by SANS.

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