• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.859-860
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• 2006

TiC-$TiB_2$-SiC system was a ternary eutectic, whose eutectic composition was 34TiC-$22TiB_2$-44SiC (mol%). TiC-$TiB_2$-SiC ternary eutectic composite were synthesized by a floating zone method using TiC, $TiB_2$ and SiC powders as starting materials. The TiC-$TiB_2$-SiC eutectic composite showed a lamellar texture. TiC(022), $TiB_2(010)$ and SiC(111) of the eutectic composite were perpendicular to the growth direction. TiC-$TiB_2$-SiC ternary eutectic composite had specific relationship among the crystal planes: TiC[011]//$TiB_2[010]$//SiC[112], TiC(200)//$TiB_2$(001)//SiC(402) and $TiC(1\bar{1}1)$//$TiB_2(101)$//SiC(220).

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.402-409
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• 2013

The objective of this study was to develop a synthesis process for ${\beta}$-SiC powders to reduce the synthesis temperature and to control the particle size and to prevent particle agglomeration of the synthesized ${\beta}$-SiC powders. A phenol resin and TEOS were used as the starting materials for the carbon and Si sources, respectively. $SiO_2$-C hybrid precursors with various C/Si mole ratios were fabricated using a conventional sol-gel process. ${\beta}$-SiC powders were synthesized by a carbothermal reduction process using $SiO_2$-C hybrid precursors with various C/Si mole ratios (1.6 ~ 2.5) fabricated using a sol-gel process. In this study, the effects of excess carbon and the addition of Si powders to the $SiO_2$-C hybrid precursor on the synthesis temperature and particle size of ${\beta}$-SiC were examined. It was found that the addition of metallic Si powders to the $SiO_2$/C hybrid precursor with excess carbon reduced the synthesis temperature of the ${\beta}$-SiC powders to as low as $1300^{\circ}C$. The synthesis temperature for ${\beta}$-SiC appeared to be reduced with an increase of the C/Si mole ratio in the $SiO_2$-C hybrid precursor by a direct carburization reaction between Si and excess carbon.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.6
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• pp.487-490
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• 2010

This paper describes the elecrtical and optical characteristics of $N_2$ doped porous 3C-SiC films. Polycrystalline 3C-SiC thin films are anodized by $HF+C_2H_5OH$ solution with UV-LED exposure. The growth of in-situ doped 3C-SiC thin films on p-type Si (100) wafers is carried out by using APCVD (atmospheric pressure chemical vapor deposition) with a single-precursor of HMDS (hexamethyildisilane: $Si_2(CH_3)_6)$. 0 ~ 40 sccm $N_2$ was used for doping. After the growth of doped 3C-SiC, porous 3C-SiC is formed by anodization with $7.1\;mA/cm^2$ current density for anodization time of 60 sec. The average pore diameter is about 30 nm, and etched area is increased with $N_2$ doping rate. These results are attributed to the decrease of crystallinity by $N_2$ doping. Mobility is dramatically decreased in porous 3C-SiC. The band gaps of polycrystalline 3C-SiC films and doped porous 3C-SiC are 2.5 eV and 2.7 eV, respectively.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.538-545
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• 2009

The SiC-$ZrB_2$ composites were fabricated by combining 30, 35, 40 and 45vol.% of Zirconium Diboride (hereafter, $ZrB_2$) powders with Silicon Carbide (hereafter, SiC) matrix. The SiC-$ZrB_2$ composites, the sintered compacts, were produced through Spark Plasma Sintering (hereafter, SPS), and its physical, electrical, and mechanical properties were examined. Also, the thermal image analysis of the SiC-$ZrB_2$ composites was examined. Reactions between $\beta$-SiC and $ZrB_2$ were not observed via X-Ray Diffractometer (hereafter, XRD) analysis. The relative density of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$, and SiC+45vol.%$ZrB_2$ composites were 88.64%, 76.80%, 79.09% and 88.12%, respectively. The XRD phase analysis of the sintered compacts demonstrated high phase of SiC and $ZrB_2$ but low phase of $ZrO_2$. Among the SiC-$ZrB_2$ composites, the SiC+35vol.%$ZrB_2$ composite had the lowest flexural strength, 148.49MPa, and the SiC+40vol.%$ZrB_2$ composite had the highest flexural strength, 204.85MPa, at room temperature. The electrical resistivities of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$ and SiC+45vol.%$ZrB_2$ composites were $6.74\times10^{-4}$, $4.56\times10^{-3}$, $1.92\times10^{-3}$, and $4.95\times10^{-3}\Omega{\cdot}cm$ at room temperature, respectively. The electrical resistivities of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$ SiC+40vol.%$ZrB_2$ and SiC+45[vol.%]$ZrB_2$ composites had Positive Temperature Coefficient Resistance (hereafter, PTCR) in the temperature range from $25^{\circ}C$ to $500^{\circ}C$. The V-I characteristics of the SiC+40vol.%$ZrB_2$ composite had a linear shape. Therefore, it is considered that the SiC+40vol.%$ZrB_2$ composite containing the most outstanding mechanical properties, high resistance temperature coefficient and PTCR characteristics among the sintered compacts can be used as an energy friendly ceramic heater or electrode material through SPS.

• 연구논문집
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• s.26
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• pp.103-112
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• 1996

$Al_2O_3/SiC$ Hybrid-Composite has been fabricated by conventional powder process. The addition of $\alpha-Al_2O_3$ as seed particles in the transformation of $\gamma-Al_2O_3 to $\alpha-Al_2O_3$ provided a homogeneity of the microstructure, resulting in increase of mechanical properties. The grain growth of $Al_2O_3$ are significantly surpressed by the addition of nano-sized. SiC particles, increasing in fracture strength. The addition of SiC plates to $Al_2O_3$ nano-composite decreased the fracture strength, but increased the fracture toughness. Coated SiC plates with nitrides such as BN and /SiC$Si_3N_4$ enhanced fracture toughness much more than uncoated SiC plates by inducing crack deflection.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.770-776
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• 2009

The composites were fabricated by adding 0, 15, 30, 45[vol.%] $ZrB_2$ powders as a second phase to SiC matrix. The physical, mechanical and electrical properties of electroconductive SiC ceramic composites by spark plasma sintering(SPS) were investigated. Reactions between ${\beta}$-SiC and $ZrB_2$ were not observed in the XRD and the phase analysis of the electroconductive SiC ceramic composites. The relative density of mono ${\beta}$-SiC, ${\beta}$-SiC+15[vol.%]$ZrB_2$, ${\beta}$-SiC+30[vol.%]$ZrB_2$ and ${\beta}$-SiC+45[vol.%]$ZrB_2$ composites are respectively 99.24[%], 87.53[%], 96.41[%] and 98.11[%] Phase analysis of the electroconductive SiC ceramic composites by XRD revealed mostly of ${\beta}$-SiC, $ZrB_2$ and weakly of $ZrO_2$ phase. The flexural strength showed the lowest of 114.44[MPa] for ${\beta}$-SiC+15[vol.%]$ZrB_2$ powders and showed the highest of 210.75[MPa] for composite no added with $ZrB_2$ powders at room temperature. The trend of the mechanical properties of the electroconductive SiC ceramic composites is accorded with the trend of the relative density. The electrical resistivity of the electroconductive SiC ceramic composites decreased with increased $ZrB_2$ contents. The electrical resistivity of mono ${\beta}$-SiC, ${\beta}$-SiC+15[vol.%]$ZrB_2$, ${\beta}$-SiC+30[vol.%]$ZrB_2$ and ${\beta}$-SiC+45[vol.%]$ZrB_2$ composites are respectively $4.57{\times}10^{-1},\;2.13{\times}10^{-1},\;2.68{\times}10^{-2}\;and\;1.99{\times}10^{-2}[{\Omega}{\cdot}cm]$ at room temperature. The electrical resistivity of mono ${\beta}$-SiC and ${\beta}$-SiC+15[vol.%]$ZrB_2$ are negative temperature coefficient resistance(NTCR) in temperature ranges from $25[^{\circ}C]\;to\; 100[^{\circ}C]$. The electrical resistivity of ${\beta}$-SiC+30[vol.%]$ZrB_2$ and ${\beta}$-SiC+45[vol.%]ZrB_2$ are positive temperature coefficient resistance(PTCR) in temperature ranges from $25[^{\circ}C]\;to\;100[^{\circ}C]$. It is convinced that ${\beta}$-SiC+30[vol.%]$ZrB_2$ composites by SPS for heater or ignitors can be applied.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1757-1763
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• 2009

The composites were fabricated by adding 0, 15, 20, 25[vol.%] Zirconium Diboride(hereafter, $ZrB_2$) powders as a second phase to Silicon Carbide(hereafter, SiC) matrix. The physical, mechanical and electrical properties of electroconductive SiC ceramic composites by Spark Plasma Sintering(hereafter, SPS) were examined. Reactions between ${\beta}-SiC$ and $ZrB_2$ were not observed in the XRD analysis. The relative density of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ composites are 90.93[%], 74.62[%], 74.99[%] and 72.61[%], respectively. The XRD phase analysis of the electroconductive SiC ceramic composites reveals high of SiC and $ZrB_2$ and low of $ZrO_2$ phase. The lowest flexural strength, 108.79[MPa], shown in SiC+15[vol.%] $ZrB_2$ composite and the highest - 220.15[MPa] - in SiC+20[vol.%] $ZrB_2$composite at room temperature. The trend of the mechanical properties of the electroconductive SiC ceramic composites moves in accord with that of the relative density. The electrical resistivities of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ composites are 4.57${\times}10^{-1}$, 2.13${\times}10^{-1}$, 1.53${\times}10^{-1}$ and 6.37${\times}10^{-2}$[${\Omega}$ cm] at room temperature, respectively. The electrical resistivity of mono SiC, SiC+15[vol.%]$ZrB_2$. SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ are Negative Temperature Coefficient Resistance(hereafter, NTCR) in temperature ranges from 25[$^{\circ}C$] to 100[$^{\circ}C$]. The declination of V-I characteristics of SiC+20[vol.%]$ZrB_2$ composite is 3.72${\times}10^{-1}$. It is convinced that SiC+20[vol.%]$ZrB_2$ composite by SPS can be applied for heater or electrode above 1000[$^{\circ}C$]

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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• pp.18-19
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• 2002

Si 웨이퍼제조 시 나오는 페슬러지에서 SiC 연마재와 절삭유를 분리해내면 Si 분말을 얻을 수 있다. 본 연구에서의 SiC는 폐슬러지 Si 분말에 C 분말을 혼합하여 제조할 수 있다. Si-C-O 3성분계는 Si, $SiO_2$, SiC, C 4개의 응축상과 CO, SiO, $CO_2$, $O_2$ 4개의 기체상이 가능하고 생성물들 간의 평형관계를 깁스 자유에너지에 의해 평형 반응식이 계산되어질 수 있다. 계산된 평형 반응식은 2개의 SiO, CO 분압이 각각 X, Y 좌표평면에 나타나는 상안정도를 그려볼 수 있다. 상안정도에서 자유도가 2인 경우는, $SiO_2$가 불안정하므로 SiC와 C가 공존하는 영역에서 온도를 독립 변수로 놓으면 나머지 독립 변수는 SiO 나 CO 기체 분압 둘 중 하나가 되어 하나의 직선으로 나타낼 수 있다. 직선을 경계로 각 응축상들의 안정영역을 하나의 좌표평면에 나타낸 후 온도에 따른 SiC의 안정영역을 알아본다.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1155-1159
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• 1999

Thin film solar cells on a glass/$SnO_2$ substrate with p-SiC/i-Si/n-Si heterojunction structures were fabricated using a plasma-enhanced chemical-vapor deposition system. The photovoltaic properties of the solar cells were examined with varying the gas phase composition, x=$CH_4/\;(SiH_4+CH_4)$, during the deposition of the p-SiC layer. In the range of x=0~0.4, the efficiency of solar cell increased because of the increased band gap of the p-SiC window layer. Further increase in the gas phase composition, however, led to a decrease in the cell efficiency probably due to in the increased composition mismatch at the p-SiC/i-Si layers. As a result, the efficiency of a glass/$SnO_2$/p-SiC/i-SiC/i-Si/n-Si/Ag thin film solar cell with $1cm^2$ area was 8.6% ($V_{oc}$=0.85V, $J_{sc}$=16.42mA/$cm^2$, FF=0.615) under 100mW/$cm^2$ light intensity.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.4
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• pp.358-369
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• 1995

Surface structure and adhesion by the reaction between thin metal films and SiC were studied at temperatures between 550 and $1450^{\circ}C$ for various times. The reaction with the formation of various silicides was initially observed above $850^{\circ}C$ for SiC/Co system and $650^{\circ}C$ for SiC/Ni system. The cobalt reacted with SiC and consumed completely at $1050^{\circ}C$ for 0.5 h and the nickel at $950^{\circ}C$ for 2 h. The observed CoSi phase in SiC/Co and Ni$_2$Si phase in SiC/Ni are thermodynamically stable in the reaction zone up to 125$0^{\circ}C$ and $1050^{\circ}C$ respectively. Carbon was crystallized as graphite above $1450^{\circ}C$ for SiC/Co reaction surface and $1250^{\circ}C$ for SiC/Ni. The critical loads of the thin metal films on SiC substrate were qualitatively compared in terms of the scratch test method. At temperatures between 850 and $1050^{\circ}C$, relatively higher values of 20~33 N were observed for SiC/Ni couples.