Diamond 박막 성장에 미치는 Si 표면 영향의 AES에 의한 연구

이철로(C. R. Lee),신용현(Y. H. Shin),임재영(J. Y. Leem),정광화(K. H. Chung),천병선(B. S. Chun) 한국진공학회(ASCT) 1993 Applied Science and Convergence Technology Vol.2 No.2

Si 기판 표면상태 변화와 관련된 핵생성 자유에너지 증가에 따른 다이아몬드 박막성장 거동을 관찰하였다. 표면 연마조건 변화에 따른 3가지 기판(A-Si, B-Si, C-Si) 위에 동일한 성장조건으로 다이아몬드를 성장하였으며, 이때 형상인자와 관련된 자유에너지 관계는 ΔG_(A-Si)<ΔG_(B-Si)<ΔG_(C-Si)이다. AES, SEM, XRD, RHEED에 의해 각각의 박막 A, B, C를 조사한 결과, 핵생성 자유에너지가 가장 적은 A 박막은 (100) (110) 면이 지배적인 고품위 다이아몬드 박막이다. 자유에너지가 A에 비해 다소 적은 B 박막은 (111) 면이 지배적인 8면체 다이아몬드 박막이고, 자유에너지가 가장 적은 C 박막은 흑연이 많이 함유된 구상의 다이아몬드이다. The effect of nucleation free energy related to Si surface states on diamond film growth behavior has been studied. At first, the three kinds of diamond thin films (A, B, C) were deposited on various Si substrates (A-Si, B-Si, C-Si) whose surfaces were polished with 1 ㎛ diamond paste, 6 ㎛ Al₂O₃ powder and 12 ㎛ Al₂O₃ powder respectively. And then, relative nucleation free energy calculated is ΔG_(A-Si)<ΔG_(B-Si)<ΔG_(c-Si) Although there are some difference in grain size, shape and nucleation site, the thin films on A-Si and B-Si were diamond including a small amount of DLC which was confirmed by AES, SEM, XRD and RHEED. Namely, the diamonds of films (B) were not nucleated in scratches but in dents and larger in grain size compare with the film (C) of which diamond were nucleated not only scratches but also dents. And, the sphere diamond which is not general shape was grown on C-Si. After all, the sphere was turned out to be the diamond including much graphite as a result of the AES in situ depth profiling. Consequently, the diamond shape and quality grown on Si were changed from the crystal which the (100) and (110) planes were predominent to the crystal in which (111) plane was predominent, and next to sphere shape diamond including much graphite according as the nucleation free energy increases.

은(Ag)계 활성금속을 사용한 질화 알미늄(AlN)과 Cu의 브레이징

허대,김대훈,천병선,Huh, D.,Kim, D.H.,Chun, B.S. 대한용접접합학회 1995 대한용접·접합학회지 Vol.13 No.3

Aluminium nitride(AlN) is currently under investigation as potential candidate for replacing alumium oxide(Al$_{2}$ $O_{3}$) as a substrate material for for electronic circuit packaging. Brazing of aluminium nitride(AlN) to Cu with Ag base active alloy containing Ti has been investigated in vacuum. Binary Ag$_{98}$ $Ti_{2}$(AT) and ternary At-1wt.%Al(ATA), AT-1wt.%Ni(ATN), AT-1wt.% Mn(ATM) alloys showed good wettability to AlN and led to the development of strong bond between brate alloy and AlN ceramic. The reaction between AlN and the melted brazing alloys resulted in the formation of continuous TiN layers at the AlN side iterface. This reaction layer was found to increase by increase by increasing brazing time and temperature for all filler metals. The bond strength, measured by 4-point bend test, was increased with bonding temperature and showed maximum value and then decreased with temperature. It might be concluded that optimum thickness of the reaction layer was existed for maximum bond strength. The joint brazed at 900.deg.C for 1800sec using binary AT alloy fractured at the maximum load of 35kgf which is the highest value measured in this work. The failure of this joint was initiated at the interface between AlN and TiN layer and then proceeded alternately through the interior of the reaction layer and AlN ceramic itself.

P형 Fe(Mn)Si₂ 열전재료 분말의 성형 및 미세조직

심재식,홍순직,천병선,Shim, J.S.,Hong, S.J.,Chun, B.S. 한국분말야금학회 2008 한국분말재료학회지 (KPMI) Vol.15 No.5

The effects of the dopant (Mn) ratio on the microstructure and thermoelectric properties of $FeSi_2$ alloy were studied in this research. The alloy was fabricated by a combination process of ball milling and high pressure pressing. Structural behavior of the sintered bulks were systematically investigated by XRD, SEM, and optical microscopy. With increasing dopan (Mn) ratio, the density and ${\varepsilon}-FeSi$ phase of the sintered bulks increased and maximum density of 94% was obtained in the 0.07% Mn-doped alloy. The sintered bulks showed fine microstructure of ${\alpha}-Fe_{2}Si_{5}$, ${\varepsilon}-FeSi$ and ${\beta}-FeSi_2$ phase. The semiconducting phase of ${\beta}-FeSi_2$ was transformed from ${\alpha}-Fe_{2}Si_{5}+{\varepsilon}-FeSi$ phase by annealing.

제 2 발표장 : 나노결정 구리의 기계적 성질의 복합재료모델에 관한 연구

김형섭,조성석,천병선 ( H . S . Kim,S . S . Cho,B . S. Chun ) 한국복합재료학회 1996 한국복합재료학회 학술발표대회 논문집 Vol.- No.2

Sol - Gel 법에의한 YBa2 Cu3 O7-x 분말제조 및 소결특성

원창환(C . W . Won),천병선(B . S . Chun) 대한금속재료학회 1993 분말야금 Vol.5 No.-

수소함유 다이아몬드 박막과 MS 및 MIS 다이아몬드 다이오드의 전기적 특성

이철로(C. R. Lee),임재영(J. Y. Leem),천병선(B. S. Chun) 한국진공학회(ASCT) 1994 Applied Science and Convergence Technology Vol.3 No.1

기전력 증가에 따라 균일 두께로 4종류 다이아몬드 박막을 성장하였다. 이들에 대해 성장 직후 및 진공소둔 후 전기전도도를 조사한 결과 성장 중 기전력이 증가하면 다이아몬드 결정내에 원자상 수소의 혼입이 증가되어 높은 전기전도도를 나타낸다. 고진공소둔에 의해 탈가스를 하면 원자상 수소가 제거되어 전기전도도를 감소시킬 수 있다. 그러므로 다이아몬드 박막을 유전체 박막에 응용하기 위해서는 진공 탈가스가 필요하다. MS 및 MIS구조 다이아몬드 다이오드를 제조하여 정류특성을 평가한 결과 저농도 MS구조는 극히 낮은 정류특성을 나타내며 고농도는 Ohmic 거동을 하였다. MIS구조에서는 저농도 및 고농도 모두 우수한 정류특성을 나타냈다. 그러므로 다이아몬드 박막으로 MIS구조에 의한 다이오드를 제조하므로써 고속, 고출력 전자소자 및, 고온, 고방사, 원자로, 우주 등 열악한 환경하에서 사용될 수 있는 전자소자의 가능성이 높다고 사료된다. Four kinds of diamomd thin film of same thickness were grown as the potential between substrates and filament increases. The electrical conductivity increase as the potential increases due to the increment of atomic hydrogen content in the films. But it is possible to decrease the electrical conduction for using it to dielectric film by degassing of atomic hydrogens in high vacuum. The MS and MIS diamond semiconductor diodes were made with Schottky and Ohmic contacts in order to evaluate the rectifing characteristics. High and low doped MS diodes showed Ohmic behavior and low rectification respectively. But both high and low doped MIS diodes showed the excellent rectifing behaviors. Therefore, it is possible to obtain the MIS diode having excellent rectifing behavior using diamond thin film usable under high temperature, high radition, nuclear reactor, bad enviromental condition and etc.

Ni-0.9wt%P 전주층의 기계적 특성 및 미세조직

정현규(H. K. Jung),서무홍(M. H. Seo),김정수(J. S. Kim),천병선(B. S. Chun),김승호(S. H. Kim) 한국표면공학회 2001 한국표면공학회지 Vol.34 No.4

EACVD로 Si 위에 성장한 다이아몬드 박막의 계면 접합강도

이철로(C. R. Lee),박재홍(J. H. Park),임재영(J. Y. Leem),김관식(K. S. Kim),천병선(B. S. Chun) 한국진공학회(ASCT) 1993 Applied Science and Convergence Technology Vol.2 No.3

필라멘트와 Si 기판 사이의 기전력을 20, 80, 140, 200V로 증가시키면서 EACVD에 의하여 성장된 다이아몬드 박막에 대하여 다이아몬드/Si 계면분석 및 계면강도를 측정하였다. 주사형전자현미경(SEM), 고분해능투과형전자현미경(HRTEM), 오제이전자분석기(AES)에 의해 계면상태를 분석한 결과, 기전력 증가에 따라 활성탄화수소 이온(C_mH_n^-) 에너지가 증가되어져 C_mH_n^-이 Si내로 침투(Impringement)가 증가되고 침투된 높은 에너지의 C_mH_n^-이 Si과 화학결합하여 생성되는 SiC층 깊이 및 농도 분포도 증가된다. 풀 시험(Pull test)에 의한 계면강도 측정 결과, SiC층 깊이 및 농도분포가 증가할수록 계면강도가 증가하였다. 관찰된 파면과 파면의 X-선 메핑 결과 및 HRTEM과 AES에 의한 분석 결과, 기전력 증가에 따라 공극율이 적고 치밀한 다이아몬드 박막이 성장된다. 그리고 생성되는 SiC층 농도 및 깊이 분포가 증가함에 따라 다이아몬드/Si 계면이 강화되고, 상대적으로 파괴는 다이아몬드/Si 계면이 아닌 SiC층이나 Si 내부에서 발생된다. 결국, 기전력을 증가하여 활성탄화수소 이온의 에너지를 증가함으로써 계면강도가 우수하며 공극율이 매우 적고 치밀한 다이아몬드 박막을 성장할 수 있다. The diamond thin films on Si which 20 V (Film A), 80 V (Film B), 140 V (Film C) and 200 V (Film D) had been applied respectively between filament and Si substrates during growth were analysed with SEM, HRTEM and AES. Judging from those results, the diffusion of carbon increased due to the increment of the energy of active hydrocarbon ion (C_mH_n^-) and also the SiC layers were formed as the result of chemical bonding of C_mH_n^- with Si. The amount and depth of SiC layer increased as the potentials increased. The interface adhesion of these films were also measured with Pull test which is the most accurate and general method in evaluation of thin film adhesion. The film (D) which SiC was formed most deeply and widely exhibited the most adhesion in diamond/Si interface. Meanwhiles, the film (A) which had most shallow SiC layer and low SiC concentration exhibited very weak adhesion compare to film (D). Judging from the observation and X-Ray Mapping of fracture surface, the film (D) was fractured in Si below interface and the film (A) was fractured in diamond thin film/Si interface. Also, there are many voids in film (A) and a little in film (D). Conclusively, it is possible to grow the high strength and condensed diamond thin film without pores because the energy of active hydrocarbon ion was increased by elevation of potentials during growth.

텅스텐 중합금의 냉간가공 및 Ageing 효과에 관한 연구

천병선,송흥섭,김은표,이성,노준웅,백운형 대한금속재료학회(대한금속학회) 1992 대한금속·재료학회지 Vol.30 No.3

Tungsten heavy alloys are successful combinations of strong W grain and ductile Ni base matrix. Its high density and strength combined with excellent ductility are the principal advantages of these alloys. The purpose of this study was to understand the effects of cold working and post-ageing treatments on the mechanical properties using the classical approach of sintering compacts from a mixture of 93W-4. 9Ni-2.1Fe system. By using the ageing treatment, the strength and hardness were increased with ageing temperatures and showed maximum strength at 600℃ for the 15% cold worked specimens; whereas, ductility was minimum. Strengthening by the ageing treatment might be attributed to the very fine dispersed precipitates in W grains.

급속응고한 고망간 합금강 박판의 미세조직 및 기계적 성질에 미치는 V 첨가원소 및 열처리 영향

김형수,조성석,최창범,천병선 대한금속재료학회(대한금속학회) 1990 대한금속·재료학회지 Vol.28 No.2

We have investigated the effects of the microstructure and mechanical properties with V content and heat treatment on the rapidly solidified V added Fe-13 Mn-1.2C steel strips which were produced by a twin roll melt-quenching method. Regardless of the V content, solidification process typically took place by primary austenite formation and then the residual liquid phase formed austenite by massive transformation. In melt-quenched, the austenite to ferrite transformation was suppressed, resulting in only austenite. As the V content increased, the equiaxed structure region increased and the secondary dendrite arm spacing became a little wider. With the increase in V content, the refining of austenite grain size after heat treatment was accelerated because the increase in the formation of carbides suppressed the grain growth. As 0.2%Y.S. was increased with increasing V content, a relation between it and grain size as a function of V content can be expressed as the following equation. 0.2% Y.S.(㎏/㎟)=22.05+7.4/√D The mechanism of the large strengthening effect of V on the 0.2% Y.S. was considered to be attributable to the grain refining by V addition and the large increase of Petch constan