• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1993.12a
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• pp.35-38
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• 1993

질화규소는 고온에서 고강도, 고경도, 내열성, 내식성 등의 우수한 성질을 가지고 있기 때문에 열교환기, 공구, 기계밀봉(mechanical seal), 자동차용 엔진부품중의 피스톤 및 실린더 링 등의 중요한 부품의 재료로 크게 부목받고 있다. 이러한 질화 규소의 고온에서의 마모, 마찰거동이 중요한 부품으로의 활용범위를 넓히고 또한 기능성을 향상시키기 위해서 고온에서의 마모, 마찰거동에 대한 연구 및 이해가 절대적으로 필요하다. 공유결합성이 강한 질화규소의 소결시에 첨가되는 첨가제나 제조공정에서 들어갈 수 있는 불순물들은 소결체의 입자모양이나 입계에 존재하는 상의 점도를 변화시켜 고온에서의 기계적성질을 저하시키는 것으로 알려졌다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.209-209
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• 2003

기계가공용으로 개발된 3성분계 Ti-Si-N 코팅막은 약 40㎬이상의 초고경도이며, 그 미세구조는 나노입자의 TiN결정과 비정질 Si$_3$N$_4$로 이루어져 있다. Ti-Si-N 코팅의 경도는 극소량 Si를 첨가함에 따라 급격히 증가하였으며, 7.7at%에서 약 45㎬이었다. 그 이상에서는 감소하였다. 본 연구는 Ti-Si-N 코팅에서 규소첨가에 따른 박막에 형성하는 질화규소 또는 규소의 특성을 조사하기 위하여 질화규소 박막을 제조하여 그 특성 및 기계적 성질을 조사하였다. 스퍼터링 방법으로 제조한 질화규소 박막의 표면 및 내부구조를 광학현미경, 주사전자현미경, 투과전자현미경 그리고 AFM으로, 정성 및 정량을 EPMA와 EDS로, 결정성을 박막 엑스선회 절분석기로, 화학 결합구조을 XPS으로 분석하였다. 그리고 나노인덴터를 이용하여 박막의 경도와 탄성계수를 조사하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.2
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• pp.61-67
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• 2005

In this study a new growing method of silicon nitride whiskers in the inside of large pores made intentionally during the sintering was conducted. Pore size, pore vol%, and nitrogen pressure were used as experimental variables. Silicon nitride whiskers were well grown in the inside of pores with low pore vol% range from 14 to 27 but not grown with high pore vol% such as 39 and 50. On the other hand, pore size and nitrogen pressure did not have any influence on the whisker growth. Therefore the most important factor to grow silicon nitride whisker in the inside of large pores during sintering was to make pores isolated or closed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1013-1019
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• 2007

Amorphous silicon and silicon-nitride films were deposited using plasma-enhanced chemical vapor deposition (PECVD) method at $150^{\circ}C$. As fraction of $H_2$ in source gas was increased, characteristics of low-temperature silicon-nitride films approached those of conventional high-temperature films; the refractive index approached 1.9 and the ratio of nitrogen-hydrogen bonds to silicon-hydrogen bonds increased. And also, as fraction of $H_2$ in source gas was increased, characteristics of low-temperature silicon films approached those of conventional high-temperature films; refractive index and optical band gap approached 4.2 and 1.8 eV, and $[Si-H]/([Si-H]+[Si-H_2])$ increased. Lower RF power and process-pressure made the amorphous silicon films to be better properties. Increase of $H_2$ ratio seemed as the common factor to get reliable amorphous silicon and silicon-nitride films for thin-film-transistors (TFTs) at low temperature.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.129.1-129.1
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• 2016

반도체, 디스플레이, PC 등 전자기기의 경우 소자 내 발생된 열로 인해 기기의 성능 및 효율, 수명 등이 감소하기 때문에 이러한 내부 열을 외부로 방출시켜줄 필요가 있다. 일반적으로 heat pipe나 냉각 팬(fan) 등의 외부장치에 의해 강제적으로 냉각해주는 기술이 있지만 휴대용 디바이스와 같이 작은 전자기기의 경우 소자 자체적으로 열전도 특성이 뛰어난 기판을 사용하여 열전도에 의해 열이 소자 밖으로 방출될 수 있도록 방열 설계를 해주어야 한다. 따라서 소자 전체를 지지해주고 열전도에 의해 방열 기능을 해주는 방열기판에 대한 관심이 증가하고 있다. 현재 가장 많이 사용되어지는 세라믹 방열기판으로는 알루미나가 있지만 보다 소자의 집적화와 고성능화로 인하여 열전도도가 높은 질화규소 기판의 요구가 증대되고 있다. 하지만 이러한 질화규소기판에 금속전극을 형성하는 기술은 종래의 알루미나 기판에 이용한 DPC(Direct Plated Copper), DBC(Direct Bonded Copper)기술을 적용할 수 없다. 그래서 현재는 메탈블레이징을 이용하여 전극을 형성하지만 공정비용 및 대형기판에 형성이 어려운 단점이 있다. 따라서, 본 연구에서는 질화규소 방열기판에 전기화학공정을 통하여 밀착력이 우수한 금속 전극 회로층 형성에 대한 연구를 진행하였다. 질화규소 방열기판에 무전해 Ni 도금을 통하여 금속층을 형성하는데 이 때 세라믹 기판과 금속층 사이의 낮은 밀착력을 향상시키기 위해 습식공정을 통하여 표면처리를 진행하였다. 또한 촉매층을 $Pd-TiO_2$ 층을 이용하여 무전해 도금공정을 이용하여 Ni, 전극층을 형성하였다. 질화규소 표면에 OH기 형성을 확인하기 위해 FT-IR(Fourier-transform infrared spectroscopy)분석을 실시하였으며 OH 그룹 형성 및 silane의 화학적 결합으로 인해 금속 전극층의 밀착력이 향상된 것을 cross hatch test 및 scratch test를 통해 확인하였고 계면 및 표면형상 특성 등을 분석하기 위해 TEM(Transmission electron microscopy), SEM(Scanning electron microscopy), AFM(Atomic-force microscopy)등의 장비를 이용하였다.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.89-93
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• 2018

Ceramic substrates applied to power modules of electric vehicles are required to have properties of high thermal conductivity, high electrical insulation, low thermal expansion coefficient and resistance to abrupt temperature change due to high power applied by driving power. Aluminum nitride and silicon nitride, which are applied to heat dissipation, are considered as materials meeting their needs. Therefore, in this paper, the properties of aluminum nitride and silicon nitride as radiator plate materials were compared through a commercial analysis program. As a result, when the process of applying heat of the same condition to aluminum nitride was implemented by simulation, the silicon nitride exhibited superior impact resistance and stress resistance due to less stress and warping. In terms of thermal conductivity, aluminum nitride has superior properties as a heat dissipation material, but silicon nitride is more dominant in terms of reliability.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.42.2-42.2
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• 2000

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.299-307
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• 2002

In this proposed study, a new emerging shape forming technique Direct Coagulation Casting(DCC) which enables to fabricate complex-shaped ceramic parts has been investigated using colloid surface chemistry. Various process variables affected by dispersant, coagulation agent and sintering additives, have been evaluated in order to achieve highly concentrated stabilized silicon nitride suspensions. A high solid loading of 51 vol% in the dispersed silicon nitride suspension was prepared with 1.0wt% Tetraethylammonium Hydroxide (TEAH), which obtained a stable silicon nitride suspension with sintering additives $(Al_2O_3\;and\;Y_2O_3)$ in alkaline regions. The addition of hydroxyaluminium diacetate into the suspension, which decomposed at elevated temperatures, led to coagulate of a silicon nitride suspension. In a basic medium, aluminum ions precipitated to aluminum hydroxide $(Al(OH)_3)$, leading to decreased $OH^-$ concentration and, thus, coagulated suspension.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.4
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• pp.370-377
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• 1994

DC plasma torch which is a non-transferred type was constructed and silicon nitride powders were produced. Ar gas is used as a plasma gas and gas reactants with the carrier gas are introduced beneath the plasma ignition part. Two slits are attached and a reactive quenching gas is introduced through them. Using $SiCl_4 and NH_3$ as starting materials, silicon nitride powders were produced. As-produced powders were amorphous and crystalline silicon nitrides were obtained by heating at $1420^{\circ}C$ for two hours under nitrogen atmosphere. Silicon nitride phase was identified in the XRD patterns and IR spectrum, and the image of the powders before and after heating was observed from the TEM analysis.

• Korean Journal of Materials Research
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• v.8 no.4
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• pp.293-298
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• 1998

The fracture behavior of $Si_3N_4N$, coated $Si_3N_4N$-BN composite was studied by the Hertzian indentation technique. New types of contact-induced cracks were found, and it was confirmed that these cracks have cone crack geometry. Contact damage was distributed in the substrate layer, which can absorb energy, as well as in the coating layer, so the propagation of initiated cracks in the coating layer were suppressed.