질화규소의 고온마모에 미치는 Fe 불순물의 영향에 관한 연구

임대순(Dae Soon Lim),이경호(Kyoung Ho Lee),최우석(Woo Suk Choi) 고려대학교 공학기술연구소 1994 고려대학교 생산기술연구소 생기연논문집 Vol.30 No.1

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전력 트랜지스터의 특성에 미치는 다이아몬드상 카본 passivation 막의 효과

박정호,임대순,정석구,장훈,신종한,Park, Jung-Ho,Lim, Dae-Soon,Jung, Suk-Koo,Chang, Hoon,Shin, Jong-Han 대한전자공학회 1996 전자공학회논문지-A Vol.33 No.11

Because of the novel characteristics such as chemical stability, hardness, electrical resistivity and thermal conductance, diamond-like carbon (DLC) film is a suitable materials for the passivation layers. For this purpose, DLC films are synthesized under various conditions and are characterized. Adhesive stregth is excellent and increased with the increase of the hydrogen gas flow rate. The resistivity of approximately 5.3X10$^{8}{\Omega}{\cdot}cm$ is measured by automatic spreading resistance probe analysis method. The thermal conductivity of DLC films is superior to that of PSG oxide and improved by increasing the hydrogen gas flow rate. The patterning techniques of the DLC films is developed using the lift-off and RIE methods to form 5${\mu}$m line. Finally, power transistor with the DLC film as passivation layer is fabricated and analyzed. The test result shows the improsved long-term stability and higher breakdown voltage.

열분해법으로 형성된 산화크롬 박막의 자기적 특성

최현주,임대순,이전국,Choi, Hyun-Ju,Lim, Dae-Soon,Lee, Jeon-Kook 한국세라믹학회 2004 한국세라믹학회지 Vol.41 No.9

(110) 배향 TiO$_2$ 단결정 위에 성장시킨 CrO$_2$(110) 박막의 결정 구조, 미세구조와 자기적 특성의 상관 관계에 대해 연구하였다. 소스 물질로는 CrO$_3$ 분말을 사용하였으며, 열분해 화학증착법으로 CrO$_2$박막을 형성하였다. (110) 배향된 TiO$_2$루타일 단결정 위에 형성된 CrO$_2$ 박막은 (110) 방향으로 우선 배향되었고, 미세구조적으로 평활한 박막을 형성하였다. 흘려주는 산소량이 많을수록 CrO$_2$ 박막의 두께가 두꺼워지고 저항치가 낮았으며, 음의 자기저항치의 변화 및 자기 이력 곡선에서 보자력과 잔류 자화 값이 감소하는 경향을 보였다. We report the magnetic properties, microstructures, and crystal orientations of the CrO$_2$ thin films on TiO$_2$ single crystals. CrO$_2$ thin films were deposited by thermal decompositions with CrO$_3$ source materials. The microstructure of (110) oriented CrO$_2$ thin films deposited on (110) TiO$_2$ single crystals were uniform. As the oxygen flow rates increased, the resistivity, coercive field, and remnant magnetization of the CrO$_2$ thin films on TiO$_2$ single crystals decreased.

CH₄ 농도 변화가 저유전 SiOC(-H) 박막의 유전특성에 미치는 효과

신동희,김종훈,임대순,김찬배,Shin, Dong-Hee,Kim, Jong-Hoon,Lim, Dae-Soon,Kim, Chan-Bae 한국재료학회 2009 한국재료학회지 Vol.19 No.2

The development of low-k materials is essential for modern semiconductor processes to reduce the cross-talk, signal delay and capacitance between multiple layers. The effect of the $CH_4$ concentration on the formation of SiOC(-H) films and their dielectric characteristics were investigated. SiOC(-H) thin films were deposited on Si(100)/$SiO_2$/Ti/Pt substrates by plasma-enhanced chemical vapor deposition (PECVD) with $SiH_4$, $CO_2$ and $CH_4$ gas mixtures. After the deposition, the SiOC(-H) thin films were annealed in an Ar atmosphere using rapid thermal annealing (RTA) for 30min. The electrical properties of the SiOC(-H) films were then measured using an impedance analyzer. The dielectric constant decreased as the $CH_4$ concentration of low-k SiOC(-H) thin film increased. The decrease in the dielectric constant was explained in terms of the decrease of the ionic polarization due to the increase of the relative carbon content. The spectrum via Fourier transform infrared (FT-IR) spectroscopy showed a variety of bonding configurations, including Si-O-Si, H-Si-O, Si-$(CH_3)_2$, Si-$CH_3$ and $CH_x$ in the absorbance mode over the range from 650 to $4000\;cm^{-1}$. The results showed that dielectric properties with different $CH_4$ concentrations are closely related to the (Si-$CH_3$)/[(Si-$CH_3$)+(Si-O)] ratio.

MoO₃가 첨가된 Cr₂O₃ 플라즈마 용사코팅의 고온 마찰 마멸 특성

여인웅,안효석,임대순,Lyo, In-Woong,Ahn, Hyo-Sok,Lim, Dae-Soon 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.9

산화몰리브덴($MoO_3$)이 첨가된 산화크롬 용사코팅층을 제조하여 산화몰리브덴의 첨가에 따른 고온(450$^{\circ}C$)에서의 플라즈마 용사코팅층에 마찰, 마멸특성을 조사하였다. 마찰, 마멸 특성에 대한 실험을 위하여 왕복동 마멸시험장치를 사용하였다. TEM을 이용하여 코팅층의 미세 구조와 각 상들의 조성을 살펴보았다. 분석 결과에 의하면 산화몰리브덴이 입계로 분산되어 있어 코팅층의 경도와 밀도의 증가가 발생하였다. 마멸시험후 마멸면의 물리적 변화와 화학적 조성의 변화를 SEM와 XPS를 통하여 살펴보았다. 산화몰리브덴이 첨가된 코팅층에서 마찰계수의 감소를 관찰할 수 있었다. 산화몰리브덴이 첨가된 코팅의 마멸된 표면에 마찰, 마멸에 유리한 보호막의 형성이 광범위하게 일어남을 알 수 있었다. 이러한 보호막에 몰리브덴이 산화몰리브덴의 형태로 존재하는 것을 XPS 분석을 통하여 알 수 있었다. 보호막에 산화몰리브덴의 존재가 마찰계수를 감소시키는 것으로 생각된다. Tribological behavior of plasma-sprayed $Cr_2O_3$-based coatings containing $MoO_3$ at 450$^{\circ}C$ was investigated to understand the influence of $MoO_3$. A reciprocal disc-on-plate type tribo-tester was employed to examine fricition and wear behavior of the specimens. The microstructure and phase composition of the coating was characterized with Transmission Electron Microscopy(TEM). The TEM analysis indicated that $MoO_3$ was dispersed into the grain boundary, resulting in the increase of the hardness and density of the coating. Worn surfaces were investigated by scanning electron microscopy and chemistry of the worn surfaces was analyzed using a X-ray Photoelectron Spectrometer(XPS). The results showed that the friction coefficient of the $MoO_3$-added coatings was lower than that without $MoO_3$ addition. The larger protecting layers were observed at the worn surface of plasma spray coated specimens with $MoO_3$ composition in the protecting layer appears to be more favorable in reducing the friction.

RF UBM Sputtering에 의해 증착된 hBN 박막의 미세구조가 cBN 상의 핵형성에 미치는 영향

이은옥,박종극,임대순,백영준,Lee Eun-Ok,Park Jong-Keuk,Lim Dae-Soon,Baik Young-Joon 한국진공학회 2004 Applied Science and Convergence Technology Vol.13 No.4

Si(100) 기판 위에 RF UBM 스퍼터링 (Unbalanced Magnetron Sputtering) 방법을 이용하여 BN 박막을 증착하였다. 이온 충돌 에너지에 영향을 주는 증착 압력과 기판 바이어스 전압을 변화시켜, 증착된 BN박막의 미세구조와 압축응력의 변화를 살펴보았다. 높은 증착 압력에서는 hBN laminate의 정렬도가 기판 바이어스 전압이 증가함에 따라 선형적으로 증가한 반면, 낮은 증착 압력에서는 낮은 기판 바이어스 전압에서 hBN laminate의 정렬도가 높게 나타났다. hBN 박막의 응력 변화와 표면 형상은 hBN laminate의 정렬도와 밀접한 관계가 있는 것으로 관찰되었는데, 이의 적절한 조절에 의해 압축응력의 증가 없이도 hBN 박막 위에 cBN 상의 핵 형성이 일어날 수 있었다. Boron nitride thin films were deposited on Si(100) substrate by RF (Radio-frequency) UBM (Unbalanced Magnetron) sputtering system. The effect of working pressure and substrate bias voltage on microstructure and compressive stress of boron nitride thin films has been investigated. In high working pressure, the alignment of hBN laminates increased with substrate bias voltage, in low working pressure, however, it was high in low substrate bias voltage. Compressive stress evolution and surface morphology of deposited BN films are closely related with the alignment of hBN laminates. The cBN phase without high compressive stress could be nucleated on hBN thin film by controlling the alignment of hBN laminates.

TiC표면개질에서 Cl₂가스농도가 tribology특성에 미치는 효과

배흥택(Heung-Taek Bae),임대순(Dae-Soon Lim),나병철(Byung-Chul Na) 한국트라이볼로지학회 2007 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.23 No.6

Carbide-derived carbon coating has been synthesized by low temperature treatment of TiC disk with H₂/Cl₂ mixture gases. A variety of physical measurements indicated that Ti was extracted and carbon layer was formed by exposure of Cl₂ gas. The ID/IG ratio increased with increasing Cl₂ gas concentration. Wear coefficient and frictional coefficient varied with Cl₂ gas concentration. When the Cl₂ gas concentration decreased to 3.3 vol%, the friction coefficient approach a minimum. The results showed that degree of graphite crystallinity and variation of porosity due to the Cl₂ gas content were responsible for different tribology performance.

Sol-gel 법으로 합성된 SiC-C 복합분말을 사용하여 제조된 Si-SiC의 기계적 특성 및 전기저항 특성

윤성일,조경선,염미래,임대순,박상환,Youn, Sung Il,Cho, Gyung Sun,Youm, Mi Rae,Lim, Dae Soon,Park, Sang Whan 한국세라믹학회 2014 한국세라믹학회지 Vol.51 No.5

In this study, Si-SiC composites were fabricated using a Si melt infiltration method using ${\beta}$-SiC/C composite powders synthesized by the carbothermal reduction of $SiO_2-C$ precursors made from a TEOS and a phenol resin. The purity of the synthesized SiC-C composite powders was higher than 99.9993 wt% and the average particle size varied from 4 to $6{\mu}m$ with increasing carbon contents of the $SiO_2-C$ precursors. It was found that the Si-SiC composites fabricated in this study consist of ${\beta}$-SiC and residual Si, without any trace of ${\alpha}$-SiC. The 3-point bending strengths of the fabricated Si-SiC composites were measured and found to be higher than 550 MPa, although the density of the fabricated Si-SiC composite was less than $2.9g/cm^3$. The bending strengths and the densities of the fabricated Si-SiC composites were found to decrease with increasing C/Si mole ratios in the SiC-C composite powders. The specific resistivities of the Si-SiC composites fabricated using the SiC-C composite powders were less than $0.018{\Omega}cm$. With increasing C content in the SiC-C composite powders used for the fabrication of Si-SiC composites, the specific resistivity of the Si-SiC composites was found to slightly increase from 0.0157 to $0.018{\Omega}cm$.

서스펜션 플라즈마 용사법을 이용한 7.5 wt% Y₂O₃-ZrO₂ 열차폐코팅 제조 및 평가

이원준,오윤석,이성민,김형태,임대순,김성원,Lee, Won-Jun,Oh, Yoon-Suk,Lee, Sung-Min,Kim, Hyung-Tae,Lim, Dae-Soon,Kim, Seongwon 한국세라믹학회 2014 한국세라믹학회지 Vol.51 No.6

Considerable research efforts have been explored attempting to enhance the thermal durability of thermal barrier coatings (TBCs) at the high operating temperatures of gas turbines. In this study, the suspension plasma spray (SPS) process was applied to produce TBCs with a segmented structure by using an yttria-stabilized zirconia (YSZ) suspension. Four different experiment sets were carried out by controlling the ratio between surface roughness of the bond coat and feed stock size ($R_a/D_{50}$) in order to examine the effect of $R_a/D_{50}$ ratio on the microstructure of SPS-prepared coatings. When the $R_a/D_{50}$ had a high value of 11.8, a deposited thick coating turned out to have a cone-type columnar microstructure. In contrast, at the low $R_a/D_{50}$ values of 2.9 and 0.18, a deposited thick coating appeared to have a dense, vertically-cracked microstructure. However, with the very low $R_a/D_{50}$ value of 0.05 the coating was delaminated.

나노 다이아몬드가 첨가된 초고분자량 폴리에틸렌의 마모특성에 대한 연구

임동필(Dong-Phill Lim),임대순(Dae-Soon Lim) 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.37 No.-

Nano-diamonds were added to Ultra-high molecular weight polyethylene (UHMWPE) to improve the tribological properties of UHMWPE. Nano-diamonds which have a diameter of about 5-10㎚ were produced by detonation. UHMWPE/nano-diamonds composites were fabricated by hot pressing method. It is shown that friction coefficient was increased and wear resistance was improved as nano-diamonds were added to UHMWPE because of excellent mechanical properties of nano-diamonds located on UHMWPE surface.