• Journal of IKEEE
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• v.27 no.4
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• pp.630-635
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• 2023

SiC is replacing the position of silicon in the power semiconductor field due to its superior resistance to adverse conditions such as high temperature and high voltage compared to silicon, which occupies the majority of existing industrial fields. In this paper, the gate of 4H-SiC Planar MOSFET, one of the power semiconductor devices, was formed with aluminium to make the contrast and parameter values consistent with polycrystalline Si gate, and the threshold voltage, breakdown voltage, and IV characteristics were studied by varying the channel doping concentration of SiC MOSFET.

• Journal of Powder Materials
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• v.19 no.5
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• pp.379-384
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• 2012

This paper reports the microstructures and thermal conductivities of $ZrB_2$-SiC composite ceramics with size and amount of SiC. We fabricated sintered bodies of $ZrB_2$-x vol.% SiC (x=10, 20, 30) with submicron and nanosized SiC densified by spark plasma sintering. Microstructure retained the initial powder size of especially SiC, except the agglomeration of nanosized SiC. For sintered bodies, thermal conductivities were examined. The observed thermal conductivity values are 40~60 W/mK, which is slightly lower than the reported values. The relation between microstructural parameter and thermal conductivity was also discussed.

• Transactions on Electrical and Electronic Materials
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• v.11 no.2
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• pp.61-64
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• 2010

In this paper, we investigate the quality difference of SiC crystals grown by a conventional physical vapor transport method using various SiC powders. While the growth rate was revealed to be dependent upon the particle size of the SiC powder, the growth rate of SiC bulk crystals grown using SiC powder with a smaller particle size (20 nm) was definitely higher than those using lager particle sizes with $0.1-0.2\;{\mu}m$ and $1-10\;{\mu}m$, respectively. All grown 2 inch SiC single crystals were proven to be the polytype of 6H-SiC and the carrier concentration levels of about $10^{17}\;cm^3$ were determined from Hall measurements. It was revealed that the particle size and process method of SiC powder played an important role in obtaining a good quality, high growth rate, and to reduce growth temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.131-131
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• 2009

This paper describes the fabrication and characteristics of polycrystalline (poly) 3C-SiC microresonators with $3{\times}10^{17}{\sim}1{\times}10^{19}cm^{-3}$ in-situ N-doping concentrations. In this work, the crystallinity, carrier concentration and surface morphology of the grown thin films were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The 1.2 ${\mu}m$ thick cantilvers and the 0.4 ${\mu}m$ thick doubly-clamped beam microresonators with various lengths were implemented using in-situ doping poly 3C-SiC thin films. The characteristics of the poly 3C-SiC microresonators were evaluated using quartz and a laser vibrometer under vacuum at room temperature. The resonant frequencies of the SiC microresonators decreased with doping concentrations owing to the reduction of the Young's modulus of the poly 3C-SiC thin films. It was confirmed that the resonant frequencies of the poly 3C-SiC microresonators are controllable by adjusting the doping concentrations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.78-79
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• 2008

In this paper, poly 3C-SiC thin films were grown on $SiO_2$/Si by atmospheric pressure chemical vapor deposition (APCVD) using HMDS, $H_2$, and Ar gas at $1100^{\circ}C$ for 30 min, respectively. And then, palladium films were deposited on poly 3C-SiC by RF magnetron sputter. Thickness, uniformity, and quality of these samples were performed by SEM. Crystallinity and preferred orientationsof palladium were analyzed by XRD. And Pd/poly 3C-SiC schottky diodes were fabricated and characterized by current-voltage measurements. Its electric current density Js and barrier height voltage were measured as $2\times10^{-3}$ A/$cm^2$, 0.58 eV, respectively. And these devices operated about $350^{\circ}C$. From results, Pd/poly 3C-SiC devices are promising for high temperature hydrogen sensor and applications.

• Journal of Sensor Science and Technology
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• v.13 no.4
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• pp.264-269
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• 2004

This paper describes on an advanced technology of 3C-SiC/Si(100) wafer direct bonding using PECVD oxide to intermediate layer for SiCOI(SiC-on-Insulator) structure because it has an attractive characteristics such as a lower thermal stress, deposition temperature, more quick deposition rate and higher bonding strength than common used poly-Si and thermal oxide. The PECVD oxide was characterized by ATR-FTIR. The bonding strength with variation of HF pre treatment condition was measured by tensile strength measurement system. After etch-back using TMAH solution, roughness of 3CSiC surface crystallinity and bonded interface was measured and analyzed by AFM, XRD, and SEM respectively.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.5-13
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• 2006

Based on the inventions of continuous ceramic fibers, such as C, SiC, $Al_2O_3$ etc., by polymer precursor driven methods, there have been many efforts to fabricate ceramic continuous fiber reinforced composite materials with metals and ceramics matrices. The main purpose of the R & D efforts has been to produce materials for severe environments, including advanced energy systems, advanced transportation systems. The efforts have been started from the R & D of metal matrix composite materials and now the strong emphasis on ceramic matrix composites R & D can be recognized. This paper provides a brief review about the national efforts to establish advanced composite materials for future industries starting from mid 70s. C/Al and SiC/Al are the typical examples to be applied transportation systems and energy systems. The excellences in specific strength and overall mechanical properties, the excellences in environmental resistance make those materials as potential materials for advanced ocean construction and marine transportation systems. About the recent progress in ceramic fiber reinforced ceramic composites, advanced SiC/SiC composites including NITE-SiC/SiC will be introduced and the present status will be introduced.

• Journal of IKEEE
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• v.25 no.1
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• pp.1-9
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• 2021

In this paper, a 4H-SiC UMOSFET was studied which is suitable for high voltage and high current applications. In general, SiO2 is a material most commonly used as a gate dielectric material in SiC MOSFETs. However, since the dielectric constant value is 2.5 times lower than 4H-SiC, it suffers a high electric field and has poor characteristics in the SiO2/SiC junction. Therefore, the static characteristics of a device with high-k material as a gate dielectric and a device with SiO2 were compared using TCAD simulation. The results show BV decreased, VTH decreased, gm increased, and Ron decreased. Especially when the temperature is 300K, the Ron of Al2O3 and HfO2 decreases by 66.29% and 69.49%. and at 600K, Ron decreases by 39.71% and 49.88%, respectively. Thus, Al2O3 and HfO2 are suitable as gate dielectric materials for high voltage SiC MOSFET.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.11
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• pp.837-842
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• 2010

This paper describes the crystallinity, growth rate, and surface morphology of single crystalline 3C-SiC (cubic silicon carbide) thin films grown with several carbonization conditions such as temperature, $C_3H_8$ flow rate, time. In case of carbonization, an increase in the carbonization temperature caused a increase in the size and numbers of unsealed void (big black spot) which decrease the crystallinity. In addition, optimal $C_3H_8$ flow rate made carbonization layer form well and prevented the formation of voids. Also, after a period of time, the growth of carbonization layer did not increase no more. The single crystalline 3C-SiC thin films on optimal carbonized Si substrate showed an improvement on the crystallinity, the growth rate, the roughness, and the carrier concentration.

• Journal of Sensor Science and Technology
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• v.17 no.4
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• pp.256-260
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• 2008

This paper describes the mechanical properties of poly(polycrystalline) 3C-SiC thin films with various doping concentration, in which poly 3C-SiC thin fil's mechanical properties according to the n-doping concentration 1($9.2{\times}10^{15}cm^{-3}$), 3($5.2{\times}10^{17}cm^{-3}$), and 5%($6.8{\times}10^{17}cm^{-3}$) respectively were measured by nano indentation. In the case of $9.2{\times}10^{15}cm^{-3}n$-doping concentration, Young's modulus and hardness were obtained as 270 and 30 GPa, respectively. When the surface roughness according to n-doping concentrations was investigated by AFM(atomic force microscope), the roughness of poly 3C-SiC thin films doped by 5% concentration was 15 nm, which is also the best of them.