• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1075-1079
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• 2001

The R-curve for in situ-toughened SiC-30 wt% TiC composites was estimated by the indentation-strength method and compared to that of monolithic SiC with toughened microstructure. Both materials exhibited rising R-curve behavior. The SiC-TiC composites, however, displayed better damage tolerance and higher resistance to crack growth. Total volume fractions of SiC key grains, which take part in toughening mechanisms such as crack bridging and crack deflection, were 0.607 for monolithic SiC ceramics and 0.614 for SiC-TiC composites. From the microstructural characterization and the residual stress calculation, it was inferred that this superior performance of SiC-TiC composites can be attributed to stress-induced microcracking at heterophase (SiC/TiC) boundaries and some contribution from carck deflection by TiC grains.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.408-409
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• 2006

The polycrystalline 3C-SiC thin films heteroepitaxially grown by LPCVD method using single precursor 1. 3-disilabutane at $850^{\circ}C$. The crystallinity of the 3C-SiC thin film. was analyzed by XPS. Residual strain was investigated by Raman scattering. The surface morphology and voids between SiC and $SiO_2$ were measured by SEM. The grown poly 3C-SiC thin film is very good crystalline quality, surface like mirror, and low defect and strain. Therefore, the polycrystalline 3C-SiC is suitable for harsh environment MEMS applications.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.486-492
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• 1998

Silicon carbide (SiC) thin films were deposited on the porous silicon substrates by chemical vapour de-position(CVD) using MTS as a source material. The deposited films were ${\beta}$-SiC with poor crystallity con-firmed by XRD measurement. It was considered that the films showed the mixed characteistics of cry-stalline and amorphous SiC where amorphous SiC where amorphous SiC played a role of buffer layer in interface between as-dep films and Si substrate. The buffer layer reduced lattice mismatch to some extent the generally occurs when SiC films are deposited on Si. The low temperature (10K) PL (phtoluminescence) studies showed two broad bands with peaks at 600 and 720 for the films deposited at 1100$^{\circ}C$ The maximum PL peak of the crystalline SiC was observed at 600 nm and the amrophous SiC of 720 nm was also confirmed. PL peak due the amorphous SiC was smaller than that of the crystalline SiC, PL of porous Si might be disapperared due to densification during heat treatment.

• Journal of the Korean Ceramic Society
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• v.43 no.8 s.291
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• pp.509-514
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• 2006

In this study, chopped Hi-Nicalon SiC fiber Reinforced Porous Reaction Bonded SiC (RBSC) composites and it fabrication process were developed by using Si melt infiltration process. The porosity and average pore size in fabricated chopped SiC fiber reinforced porous RBSC composites were in the range of $30{\sim}40%$ and $40-90{\mu}m$, which mainly determined by the SiC powder size used as starting material and amount of residual Si in porous composites. The maximum flexural strength of chopped SiC fiber reinforced porous RBSC composite was as high as 80 MPa. The delayed fracture behavior was observed in chopped SiC fiber reinforced porous RBSC composites upon 3-point bending strength test.

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.531-536
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• 2001

SiCl$_4$/CH$_4$/H$_2$계를 사용한 플라즈마 화학증착법(PECVD)으로 실리콘(100) 기판 위에 3C-SiC막을 117$0^{\circ}C$~1335$^{\circ}C$의 온도범위에서 증착하였다. 증착온도, 유입가스비, R$_{x}$ [=CH$_4$/(CH$_4$+H$_2$)], 그리고 r.f. power를 변화시켜 증착막의 결정성에 대해 검토하였다. Thermal CVD에 비해 PECVD법은 박막의 증착속도를 향상시켰다. 증착된 3C-SiC은 (111) 면으로 최대의 우선배향성을 지님을 알 수 있었다. 실리콘 기판 위의 3C-SiC막의 결정성은 R$_{x}$값에 의존하였으며, R$_{x}$가 감소할수록 결정성이 더욱 향상되었다. Free Si가 3C-SiC막과 함께 증착되었으나, 증착온도와 r.f power가 증가함에 따라 free Si의 함량은 감소하였다. 증착온도 127$0^{\circ}C$, 유입가스비 R$_{x}$=0.04, r.f. power가 60W에서 비교적 결정성을 가진 3C-SiC막을 얻을 수 있었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.552-557
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• 1996

Microstructural development of $Si_3N_4$/20 vol% SiC nanocomposites doped 2 wt% $Al_2O_3$ and 6 wt% $Y_2O_3$ as sintering additives were analyzed by sintering interruption. Density of samples was significantly increased between $1500^{\circ}C$ and $1700^{\circ}C$, and near full density was achieved at $1800^{\circ}C$. Transformation rate from $\alpha-Si_3N_4$ to $\betha-Si_3N_4$ was increased at $1700^{\circ}C$ and $1800^{\circ}C$, and then elongated matrix grains were appeared. Small size SiC particles had suppressive effect on densification rate and transformation of $Si_3N_4$ phase.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.3
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• pp.111-116
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• 2004

The Ni/SiC Schottky diode was fabricated with the $\alpha$-SiC thin film grown by the ICP-CVD method on a (111) Si wafer. $\alpha$-SiC film has been grown on a carbonized Si layer in which the Si surface was chemically converted to a very thin SiC layer achieved using an ICP-CVD method at $700^{\circ}C$. To reduce defects between the Si and $\alpha$-SiC, the surface of the Si wafer was slightly carbonized. The film characteristics of $\alpha$-SiC were investigated by employing TEM (Transmission Electron Microscopy) and FT-IR (Fourier Transform Infrared Spectroscopy). Sputterd Ni thin film was used as the anode metal. The boundary status of the Ni/SiC contact was investigated by AES (Auger Electron Spectroscopy) as a function of the annealing temperature. It is shown that the ohmic contact could be acquired beyond a 100$0^{\circ}C$ annealing temperature. The forward voltage drop at 100A/cm was I.0V. The breakdown voltage of the Ni/$\alpha$-SiC Schottky diode was 545 V, which is five times larger than the ideal breakdown voltage of the silicon device. As well, the dependence of barrier height on temperature was observed. The barrier height from C- V characteristics was higher than those from I-V.

• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.6
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• pp.493-498
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• 2008

This Paper describes the Raman scattering characteristics of polycrystalline (Poly) 3C-SiC thin films, in which they were deposited on AlN buffer layer by APCVD using hexamethyldisilane (MHDS) and carrier gases (Ar+$H_2$). When the Raman spectra of SiC films deposited on the AlN layer of before and after annealing were worked according to growth temperature, D and G bands of graphite were measured. It can be explained that poly 3C-SiC films admixe with nanoparticle graphite and its C/Si rate is higher than ($C/Si\;{\approx}\;3$) that of the conventional SiC, which has no D and G bands related to graphite. From the Raman shifts of 3C-SiC films deposited at $1180^{\circ}C$ on the AlN layer of after annealing, the biaxial stress of poly 3C-SiC films was obtained as 896 MPa.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.3
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• pp.234-239
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• 2007

This paper describes the TiW ohmic contact characteristics under the surface treatment of the polycrystalline 3C-SiC thin film grown on $SiO_2/Si(100)$ wafers by APCVD. The poly 3C-SiC surface was polished by using CMP(chemical mechanical polishing) process and then oxidized by wet-oxidation process, and finally removed SiC oxide layers. A TiW thin film as a metalization process was deposited on the surface treated poly 3C-SiC layer and was annealed through a RTA(rapid thermal annealing) process. TiW/poly 3C-SiC was investigated to get mechanical, physical, and electrical characteristics using SEM, XRD, XPS, AFM, optical microscope, I-V characteristic, and four-point probe, respectively. Contact resistivity of the surface treated 3C-SiC was measured as the lowest $1.2{\times}10^{-5}{\Omega}cm^2$ at $900^{\circ}C$ for 45 sec. Therefore, the surface treatments of poly 3C-SiC are necessary to get better contact resistance for extreme environment MEMS applications.