• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.433-433
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• 2011

Since the concept of graphene was established, it has been intensively investigated by researchers. The unique characteristics of graphene have been reported, the graphene attracted a lot of attention for material overcomes the limitations of existing semiconductor materials. Because of these trends, economical fabrication technique is becoming more and more important topic. Especially, the epitaxial growth method by sublimating the silicon atoms on Silicon carbide (SiC) substrate have been reported on the mass production of high quality graphene sheets. Although SiC exists in a variety of polytypes, the 3C-SiC polytypes is the only polytype that grows directly on Si substrate. To practical use of graphene for electronic devices, the technique, forming the graphene on 3C-SiC(111)/Si structure, is much helpful technique. In this paper, we report on the growth of graphene on 3C-SiC(111) surface. To investigate the morphology of formed graphene on the 3C-SiC(111) surface, the radial distribution function (RDF) was calculated using molecular dynamics (MD) simulation. Through the comparison between the kinetic energies and the diffusion energy barrier of surface carbon atoms, we successfully determined that the graphitization strongly depends on temperature. This graphitization occurs above the annealing temperature of 1500K, and is also closely related to the behavior of carbon atoms on SiC surface. By analyzing the results, we found that the diffusion energy barrier is the key parameter of graphene growth on SiC surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.175-176
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• 2007

This paper describes on the characteristics of Pd thin films deposited on poly-crystalline 3C-SiC buffer layers for microsensors, in which the poly 3C-SiC was grown on Si, $SiO_2$, and AlN substrates, respectively, by APCVD using HMDS, $H_2$, and Ar gas at $1100^{\circ}C$ for 30 min. In this work, a Pd thin film was deposited on the poly 3C-SiC film by RF magnetron sputter. The thickness, uniformity, and quality of these samples were evaluated by SEM. Crystallinity and orientation of the Pd film were analyzed by XRD. Finally, Pd/poly 3C-SiC schottky diodes were fabricated and characterized by current-voltage measurements. From these results, Pd/poly 3C-SiC devices are promising for high temperature hydrogen sensors and other microsensors.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.25-28
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• 2006

This paper dealt with the LPS process for the development of high performance SiC materials, based on the detailed analysis of their microstructure and mechanical properties. The submicron SiC powder was used for the fabrication of LPS-SiC materials. A mixture of $Al_2O_3$ and $Y_2O_3$ particles was also used as a sintering additive in the LPS process. LPS-SiC materials were fabricated at different temperatures, using various additive composition ratio ($Al_2O_3/Y_2O_3$). The total amount of additive materials ($Al_2O_3+Y_2O_3$) was fixed as 10 wt%. The characterization Of LPS-SiC materials was investigated by means of SEM, XRD and three point bending test. The LPS-SiC material represented a relative density of about 98 % and a flexural strength of about 800MPa, when it was fabricated at the temperature of $1820^{\circ}C$ and the additive compositional ratio of 1.5.

• Carbon letters
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• v.6 no.2
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• pp.71-78
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• 2005

Anti-oxidation coatings are the key technique for carbon/carbon (C/C) composites used as the thermal structural materials. The microstructure and oxidation behavior of several kinds of high-performance ceramic coatings for C/C composites prepared in Northwestern Polytechnical University were introduced in this paper. It showed that the ceramic coatings such as SiC, Si-$MoSi_2$, SiC-$MoSi_2$, $Al_2O_3$-mullite-SiC and SiC/yttrium silicate/glass coatings possessed excellent oxidation resistance at high temperatures, and some of these coatings were characterized with excellent thermal shock resistance. The SiC-$MoSi_2$ coating system has the best oxidation protective property, which can effectively protect C/C composites from oxidation up to 1973 K. In addition, the protection and failure reasons of some coatings at high temperature were also provided.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.6-6
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• 2010

This paper describes that single crystal cubic silicon (3C-SiC) films have been deposited on carbonized Si(100) substrate using hexamethyldisilane(HMDS, $Si_2(CH_3)_6$) as a safe organosilane single-source precursor and a nonflammable mixture of Ar and $H_2$ gas as the carrier gas by APCVD at $1280^{\circ}C$. The 3C-SiC film had a very good crystal quality without defects due to viods, a very low residual stress.

• Journal of Sensor Science and Technology
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• v.17 no.6
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• pp.425-428
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• 2008

This paper describes the resonant characteristics of polycrystalline SiC micro resonators. The $1{\mu}m$ thick polycrystalline 3C-SiC cantilevers with different lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonance was measured by a laser vibrometer in vacuum at room temperature. For the $100{\sim}40{\mu}m$ long cantilevers, the fundamental frequency appeared at $147.2kHz{\sim}856.3kHz$. The $100{\mu}m$ and $80{\mu}m$ long cantilevers have second mode resonant frequency at 857.5.kHz and 1.14.MHz, respectively. Therefore, polycrystalline 3C-SiC resonators are suitable for RF MEMS devices and bio/chemical sensor applications.

• Journal of Sensor Science and Technology
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• v.16 no.6
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• pp.457-461
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• 2007

This paper describes the characteristics of poly (polycrystalline) 3C-SiC grown on $SiO_{2}$ and AlN substrates, respectively. The crystallinity and the bonding structure of poly 3C-SiC grown on each substrate were investigated according to various growth temperatures. The crystalline quality of poly 3C-SiC was improved from resulting in decrease of FWHM (full width half maximum) of XRD and FT-IR by increasing the growth temperature. The minimum growth temperature of poly 3C-SiC was $1100^{\circ}C$. The surface chemical composition and the electron mobility of poly 3C-SiC grown on each substrate were investigated by XPS and Hall Effect, respectively. The chemical compositions of surface of poly 3C-SiC films grown on $SiO_{2}$ and AlN were not different. However, their electron mobilities were $7.65{\;}cm^{2}/V.s$ and $14.8{\;}cm^{2}/V.s$, respectively. Therefore, since the electron mobility of poly 3C-SiC films grown on AlN buffer layer was two times higher than that of 3C-SiC/$SiO_{2}$, a AlN film is a suitable material, as buffer layer, for the growth of poly 3C-SiC thin films with excellent properties for M/NEMS applications.

• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.615-621
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• 2016

SiC-polycrystalline fiber (Tyranno SA, Ube Industries, Ltd.) shows very high heat-resistance and excellent mechanical properties up to very high temperatures. However, further increase in the strength is required. Up to now, we have already clarified the relationship between the strength and the defect-size of the SiC-polycrystalline fiber. The defects are formed during the conversion process from the raw material (amorphous Si-Al-C-O fiber) into SiC-polycrystalline fiber. In this conversion process, a degradation of the Si-Al-C-O fiber and a subsequent sintering of the degraded fiber proceed as well, accompanied by a release of CO gas and compositional changes, to obtain the dense SiC-polycrystalline fiber. Since these changes proceed in each filament, the strict control should be needed to minimize residual defects on the surface and in the inside of each filament for achieving the higher strength. In this paper, the controlling factors of the fiber strength and the fine structure will appear.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.892-895
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• 2003

This paper describes on RIE(Reactive Ion Etching) characteristics of 3C-SiC(Silicon Carbide) grown on Si(100) wafers. During RIE of 3C-SiC films in this work, $CHF_3$ gas is used to form of polymer as a side wall for excellent anisotropy etching. From this process, etch rates are obtained a $60{\sim}980{\AA}/min$ by various conditions such as $CHF_3$ gas flux, $O_2$ addition ratio, RF power and electrode distance. Also, approximately $40^{\circ}$ mesa structures are successfully formed at 100 mTorr $CHF_3$ gas flow ratio, 200 W RF power and 30 mm electrode distance. Moreover, vertical side wall is fabricated by anisotropy etching with 50% $O_2$ addition ratio and 25 mm electrode distance. Therefore, RIE of 3C-SiC films using $CHF_3$ could be applicable as fabrication process technology for high-temperature 3C-SiC MEMS applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.98-102
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• 2010

This paper describes that single crystalline 3C-SiC (cubic silicon carbide) thin films have been deposited on carbonized Si(100) substrates using hexamethyldisilane (HMDS, $Si_2(CH_3){_6}$) as a safe organosilane single precursor and a nonflammable mixture of Ar and $H_2$ gas as the carrier gas by APCVD at $1280^{\circ}C$. The deposition was performed under various conditions to determine the optimized growth condition. The crystallinity of the 3C-SiC thin film was analyzed by XRD (X-ray diffraction). The surface morphology was also observed by AFM (atomic force microscopy) and voids between SiC and Si interfaces were measured by SEM (scanning electron microscopy). Finally, residual strain and hall mobility was investigated by surface profiler and hall measurement, respectively. From these results, the single crystalline 3C-SiC film had a good crystal quality without defects due to viods, a low residual stress, a very low roughness.