Interdiffusion in Pd / Cu Multilayered Film and Its Thermal Stability

전인준(In Joon Jeon),이영백(Young Pak Lee),홍재화(Jae-Hwa Hong) 한국진공학회(ASCT) 1994 Applied Science and Convergence Technology Vol.3 No.1

확산 현상은 박막성장 과정 및 박막의 기계, 전기, 자기적 성질 이해에 중요한 역할을 한다. 열처리에 의한 상호확산 때문에 생긴 Pd/Cu 다층박막의 조성변화를 AES depth-profiling 방법을 이용해서 조사하였다. 열처리전 시료에서의 각형의 초기 조성분포가 여러 온도에서의 열처리에 의해 정현파 모양의 조성분포로 변화되었다. 조성의존성을 고려하지 않은 상호확산 계수를 정현파 분포의 진폭으로부터 구하였으며, 1.66 eV의 값을 갖는 활성화에너지는 Arrhenius plot으로부터 산출하였다. 또한 Boltzmann-Matano 방법을 사용해서 150℃에서의 조성의존 상호확산 계수도 구하였다. 열처리에 의해 조성균일화가 되는 것으로만 알려졌던 본 물질계에서도 상분리가 생성됨을 관찰하였고, 그 열처리 조건은 180℃에서 150분 보다 짧아야함을 밝혔다. In thin films, diffusion phenomena play an important role for the growth process, and in the understanding of the mechanical, electrical and magnetic properties. The change in the concentration profile due to the interdiffusion by annealing was investigated using AES depth-profiling technique on Pd/Cu multilayerd films. It was observed that the initial concentration distributions, which were almost rectangular in the unheated samples, were changed into sinusoidal ones in the annealed films at various temperatures. The concentration-independent interdiffusion coefficients were calculated from the amplitudes of sinusoidal distributions. The activation energy was determined to be 1.66 eV from the Arrhenius plot. The concentration-dependent. interdiffusivity at 150℃ was also estimated using Boltzmann-Matano method. The phase separation was observed in this material which has been known to be only homogenized. The annealing conditions turned out to be less than about 150 min at 180℃.

Physical Properties of Co-Mn-Si Films on SOI Prepared by Using a Silicidation Process

장문규,이성재,엄태윤,이영백,김진배,Taewoon Eom,Nguyen Van Dai,Young-Pak Lee,Seongjae Lee 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

We have measured the structural, magnetic, and transport properties of Co-Mn-Si films prepared on SOI wafers by using two different silicidation processes: rapid thermal annealing (RTA) at 650 ˚C for 3 and 5 min. X-ray analysis revealed that the RTA at 650˚C for 5 min produced a single-phase Co2MnSi film while the RTA at 650˚C for 3 min produced a multi-phase film composed mainly of CoSi2 and Co2MnSi. For the single-phase Co2MnSi films, we obtained a saturated magnetization of 4.1 µB/f.u. and a residual resistivity of 8.5 µ ·cm at 4.2 K, which are close to the values for single-crystalline Co2MnSi. Also, the absence of low-field magnetoresistance (MR) for the singlephase film, in contrast to the hysteretic MR for the multi-phase film, suggests that our single-phase Co2MnSi film has a single-crystal-like quality. We have measured the structural, magnetic, and transport properties of Co-Mn-Si films prepared on SOI wafers by using two different silicidation processes: rapid thermal annealing (RTA) at 650 ˚C for 3 and 5 min. X-ray analysis revealed that the RTA at 650˚C for 5 min produced a single-phase Co2MnSi film while the RTA at 650˚C for 3 min produced a multi-phase film composed mainly of CoSi2 and Co2MnSi. For the single-phase Co2MnSi films, we obtained a saturated magnetization of 4.1 µB/f.u. and a residual resistivity of 8.5 µ ·cm at 4.2 K, which are close to the values for single-crystalline Co2MnSi. Also, the absence of low-field magnetoresistance (MR) for the singlephase film, in contrast to the hysteretic MR for the multi-phase film, suggests that our single-phase Co2MnSi film has a single-crystal-like quality.

저항가열원에 의한 물질의 증발특성(Ⅰ)

정재인(Jae-In Jeong),임병문(Byung-Moon Lim),문종호(Jong-Ho Moon),홍재화(Jae-Hwa Hong),강정수(Jeong-Soo Kang),이영백(Young-Pak Lee) 한국표면공학회 1991 한국표면공학회지 Vol.24 No.1

각분해 광전자 분광법을 이용한 Pd(111)의 전자구조 연구

황도원(Do Weon Hwang),강정수(Jeongsoo Kang),홍재화(Jae Hwa Hong),정재인(Jae In Jeong),문종호(Jong Ho Moon),김건호(Kun Ho Kim),이정주(Jeoung Ju Lee),이영백(Young Pak Lee),홍순철(Soon Cheol Hong),민병일(Byung Il Min) 한국진공학회(ASCT) 1996 Applied Science and Convergence Technology Vol.5 No.1

저에너지 전자회절(low energy electron diffraction: LEED)과 각분해 광전자 분광법(angle-resolved photoemission spectroscopy: ARPES)을 이용하여 깨끗한 Pd(111) 표면의 원자구조 및 전자구조를 연구하였다. LEED 무늬는 3-fold 대칭성을 가진 전형적인 fcc (111)면에 해당하는 깨끗한 무늬가 관찰되었다. Pd(111) 표면의 Γ-M', Γ-K, Γ-M의 세 대칭선 방향을 따라 ARPES측정을 행하였고, 이 결과들로부터 4d 전자들의 실험 띠구조를 구하였다. 실험 띠구조는 이론적으로 계산한 Pd bulk 띠구조와 대체로 일치하였으며, Pd(111) 표면의 일함수의 실험값 역시 띠구조 이론에 의해 예측된 값과 잘 일치하였다. 한편 실험 띠구조는 계산한 bulk 띠구조에 비하여 에너지 준위가 Brillouin영역의 k값에 따라 0.1 ~0.8eV 정도 페르미 준위에 가깝게 나타났으며, 실험 띠폭이 이론 띠폭보다 약 0.5eV 정도 좁게 나타났다. 이러한 차이점의 원인으로 국소화된 표면 4d 전자들의 영향 및 Pd 4d bulk 전자들간의 Coulomb 상호작용 효과가 고려되었다. We have investigated atomic and electronic structures of a clean Pd(111) surface using low energy electron diffraction (LEED) and angle-resolved photoemission spectroscopy (ARPES). A typical clean LEED pattern with a 3-fold symmetry has been observed, corresponding to that for an fcc (111) surface. ARPES measurements have been performed along the Γ-M', Γ-K, Γ-M symmetry lines, from which the experimental band structure of Pd(111) has been determined. The experimental band structure and work function of Pd(111) surface are found to agree well with the calculated band structure of bulk Pd and the calculated work function of Pd(111), respectively. However, the peak positions in the experimental band structure are located closer to the Fermi level than in the theoretical band structure by 0.1~0.8 eV, depending on the k-points in the Brilouin zone. In addition, the experimental band widths are narrower than the theoretical band widths by about 0.5 eV. The effects of the localized surface Pd 4d states and the Coulomb interaction between Pd 4d bulk electrons have been discussed as possible origins of such discrepancies between experiment and theory.

In situ 고상 에피택시 방법에 의한 CoSi₂/Si(111)구조의 형성

이정주,강민성,김현수,최치규,이운환,이종덕,이영백,김건호,이정용 濟州大學校 基礎科學硏究所 1996 基礎科學硏究 Vol.9 No.2

초고진공에서 공상에피택시(solid-phase epiyaxy, SPE) 방법으로 CoSi₂를 Si(111)기판 위에 에피택시 성장시켰다. 2MeV⁴He++ ion후방산란 분광기와 사중결정 x-선 회절기 및 고분해 투과전자 현미경을 이용하여 성장된 CoSi₂의 상과 조성, 결정성, 그리고 계면의 미시구조를 조사하였다. 초고진공상태의 실온에서 Si(111)-7X7기판에 Co를 약 20 ~50 ?? 중착한 후 SPE에 의하여 실리사이드를 형성시키는 경우 600℃에서는 B-형의 CoSi₂가, 그리고 700℃에서는 A형의 CoSi₂가 선택적으로 에피택시 성장하였으며, 정합성은 B-CoSi₂[110]//Si[110] and CoSi₂(111)//Si(111)이, 그리고 700℃에서는 A-CoSi₂[110]//Si[110], CoSi₂(002)//Si(002)을 나타내었다. Epitaxial films of CoSi₂were grown on Si(111) substrates by in situ solid-phase epitaxy in a ultrahigh vacuum. The phase, the chemical composition, the crystallinity, and the microstructure of the Silicide/Si interface were investigated by 2-MeV⁴He++ ion-backscattering spectrometry, quadruple crystal X-ray diffractometry, and high-resolution transmission eletron micorscopy. High-quality films of either B-type or A-type CoSi₂ could be grown selectively on Si(111) substrates by depositing ~ 20 ~ 50 ?? of Co on a Si(111)-7X7 substrate followed by in situ annealing at 600℃ or 700℃ for 10 min. The matching face relationships are CoSi₂[110]//Si[110] and CoSi₂(111)//Si(111) by B-type CoSi₂ and CoSi₂[110]//Si[110]//Si[110] and CoSi₂(002)//Si(002) for A-type CoSi₂.

Scanning Force Microscopy를 이용한 자성 및 광자성 합금박막의 특성 분석

이광민,김기원,이영백 선문대학교·중소기업기술지원연구소 1998 선문공대 연구/기술 논문집 Vol.3 No.1

상용 회주철의 공정내에 존재하는 편상흑연의 적층결함에 관한 연구

박장식,이영백 대한금속재료학회(대한금속학회) 1994 대한금속·재료학회지 Vol.32 No.9

This study makes use of the transmission electron microscopy to examine the crystal structure of eutectic flake graphite extracted from commercial gray cast iron. The result shows that the flake graphite contains rotational stacking faults of various rotation angles. The fault is observed to occur more frequently in fine graphite flakes than in coarse flakes. The fault formation seems to be responsible for the characteristic growth mode of flake type graphite, especially in the fine flakes precipitated at high rates.

Cr-N 피막처리된 쾌삭 Ti-3Al-2V 합금의 미끄럼마모 거동

김용석,이용태,이영백,송진화,정재인 대한금속재료학회(대한금속학회) 1994 대한금속·재료학회지 Vol.32 No.1

The sliding wear behavior of the chromium nitride (CrN and a composite CrN+Cr₂N) coated Ti-3Al-2V free machining titanium alloy against heat-treated tool steel was investigated. The wear test was carried out using a ring--on-disc type tester under dry and lubricated conditions. Under the applied stress of 6.5 MPa and dry wear condition the chromium nitride coatings started to be peeled off from the substrate through pitting and micro fragmentation processes. The hard debris of the detached and crushed coatings worked as abrasives, which accelerated the wear even though the coefficient of friction was lowered by them. The effect of precleaning, such as sputtering, on the wear resistance was more significant under the dry wear condition than under the lubricated condition. Under the lubricated condition the wear resistance of the coated specimen increased a lot compared with the dry condition and the variation of the friction load decreased. Good correlation between the wear rates and low coefficient of friction was also observed under the lubricated condition.

Mg 이 상용 주철의 계면편석에 미치는 영향

박장식,지태구,이영백,홍재화 대한금속재료학회(대한금속학회) 1993 대한금속·재료학회지 Vol.31 No.8

The segregation established at the interfaces of gray and ductile iron has been examined by using Auger electron spectroscopy. This work pursued the effect of Mg on the interface chemistry as a first step to understand the microstructural modification caused by the doping addition of Mg into cast iron melts. In gray iron, S was the major segregant to both the iron/graphite and iron/iron interfaces. The effect of Mg in ductile iron was demonstrated by the clean interfaces with no such impurity segregation as observed in gray iron. Oxygen segregation was not significant at both the gray and ductile iron interfaces contrary to the results of ocher works. The segregation at, the iron/iron interface greatly supported the results obtained from the iron/graphite interface, especially with regrad to the controversial O segregation and also the segregation behavior of S as affected by Mg.