• Journal of Magnetics
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• 제13권3호
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• pp.97-101
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• 2008

We investigated the exchange bias fields at the NiFe/FeMn and FeMn/CoFe interfaces in 18.9-nm NiFe/15.0-nm FeMn/17.6-nm CoFe trilayer thin films as the annealing temperature was varied from room temperature to $250^{\circ}C$ in a vacuum for 1 hour in a magnetic field of 150 Oe. Interestingly, magnetic hysteresis (M-H) measurements showed that NiFe/FeMn/CoFe trilayer thin films exhibited a completely contrasting variation of the exchange bias fields at both the NiFe/FeMn and FeMn/CoFe interfaces with annealing temperatures. High-angle X-ray diffraction (XRD) measurements indicated the absence of any discernible effect of thermal treatment on the NiFe(111) and FeMn(111) peaks. The compositional depth profile obtained from X-ray photoelectron spectroscopy (XPS) results presented the asymmetric compositional depth profiles of the Mn and Fe atoms throughout the FeMn layer. We contend that this asymmetric compositional depth profile and the preferential Mn diffusion into the NiFe layer, compared to that into the CoFe layer, are conclusive experimental evidence of the contrasting variation of the exchange bias fields at two interfaces having a common polycrystalline FeMn(111) layer.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.275-275
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• 2012

The relative composition of $Cu(InGa)Se_2$ solar cells is one of the most important measurement issues. However, quantitative analysis of multi-component alloy films is difficult by surface analysis methods due to severe matrix effect. In this study, quantitative depth profiling analysis of CIGS films was investigated by secondary ion mass spectrometry (SIMS). The compositions were measured by SIMS using the alloy reference relative sensitivity factors derived from the certified compositions and the total counting numbers of each element. The compositions measured by SIMS were linearly proportional to those by inductively coupled plasma-mass spectrometry (ICP-MS) using isotope dilution method. In this study, the quantification measured by ICP-MS method is compared with the composition calculated by SIMS depth profiles with AR-RSFs obtained from the reference. The SIMS depth profile of CIGS thin films according to the manufacturing condition was converted into compositional depth profile.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.347-347
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• 2011

Secondary ion mass spectrometry (SIMS) was fascinated by a quantitative analysis and a depth profiling and it was convinced of a in-depth analysis of multi-layer films. Precision determination of the interfaces of multi-layer films is important for conversion from the original SIMS depth profiling to the compositional depth profiling and the investigation of structure of multi-layer films. However, the determining of the interface between two kinds of species of the SIMS depth profile is distorted from original structure by the several effects due to sputtering with energetic ions. In this study, the feasibility of 50 atomic % definition for the determination of interface between two kinds of species in SIMS depth profiling of multilayer films was investigated by Si/Ge and Ti/Si multi-layer films. The original SIMS depth profiles were converted into compositional depth profiles by the relative sensitivity factors from Si-Ge and Si-Ti alloy reference films. The atomic compositions of Si-Ge and Si-Ti alloy films determined by Rutherford backscattering spectroscopy (RBS).

• 한국안광학회지
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• 제14권1호
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• pp.63-68
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• 2009

목적: Magnetron의 세기를 비대칭으로 한 unbalanced magnetron sputtering 장치를 설계 제작하고, 이 장치를 사용하여 sus304시편 위에 TiN을 코팅할 때 산소영향을 연구하고자 한다. 방법: 코팅막의 두께를 알기 위해 실리콘 웨이퍼 위의 코팅막을 SEM으로 단면을 관찰하였고, TiN 코팅박막표면의 성분을 분석하기 위하여 XPS를 사용하였으며, 표면안쪽의 성분을 관찰하기 위해 depth profile을 하였다. 결과: XPS depth profile 데이터로부터 티타늄과 질소 뿐만 아니라 산소가 일정한 양으로 존재하며, 산소의 양은 약 65 at.%의 큰 양이 존재한다는 것을 알 수 있었다. 두께에 따른 색상변화는 세 개의 피크가 모여서 형성이 된 Ti $ 2p_{3/2}$ 피크의 모양이 두께에 따라 약간 다르다는 것을 알 수 있었다. 결론: 코팅 중에 산소가 섞여 순수한 TiN보다는 $ TiO_2$, TiN, $ TiO_{x}N_{y}$ 세가지 조합에 의해 색이 결정되는 것을 알 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.107.1-107.1
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• 2014

We have developed and commercialize a time-of-flight - medium energy ion scattering spectrometry (TOF-MEIS) system (model MEIS-K120). MEIS-K120 adapted a large solid acceptance angle detector that results in high collection efficiency, minimized ion beam damage while maintaining a similar energy resolution. In addition, TOF analyzer regards neutrals same to ions which removes the ion neutralization problems in absolute quantitative analysis. A TOF-MEIS system achieves $7{\times}10^{-3}$ energy resolution by utilizing a pulsed ion beam with a pulse width 350 ps and a TOF delay-line-detector with a time resolution of about 85 ps. TOF-MEIS spectra were obtained using 100 keV $He^+$ ions with an ion beam diameter of $10{\mu}m$ with ion dose $1{\times}10^{16}$ in ordinary experimental condition. Among TOF-MEIS applications, we report the quantitative compositional profiling of 3~5 nm CdSe/ZnS QDs, As depth profile and substitutional As ratio of As implanted/annealed Si, Ionic Critical Dimension (CD) for FinFET, Direct Recoil (DR) analysis of hydrogen in diamond like carbon (DLC) and InxGayZnzOn on glass substrate.

• 한국재료학회지
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• 제9권9호
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• pp.878-882
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• 1999

분자선증착법으로 (0001) 사파이어 기판 위에 $Al_xGa_1-_xN$ 에피층을 AlN 몰비를 변화시키면서 성장시켰다. AlN 몰비는 0.16에서 0.76까지 변화시켰으며 X선의 회절 실험과 Rutherford backscattering spectroscopy 방법을 이용하여 AlN 몰비를 결정하였다. $Al_xGa_1-_xN$ 에피층의 깊이 방향의 조성 변화를 관찰하였으며 스퍼터 시간에 대해 각 원소가 일정한 원자 농도를 가짐을 알 수 있었다. AlN 몰비의 증가에 따른 표면 특성의 변화를 관찰하기 위하여 atomic force microscopy 측정을 수행하였다. 표면에서의 입자 모양이 AlN 몰비가 변화함에 따라 원형에서 침상형태로 변화함을 알 수 있었다. 표면 입자에 대한 root mean square 값과 average roughness 값을 구하였으며 AlN 몰비를 바꿈에 따라 나타나는 변화를 관찰하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1466-1483
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• 2008

This paper discusses the development of an up-to-date computerized CPT (Cone Penetration Test) based soil engineering classification system to provide geotechnical engineers with a handy tool for their daily design activities. Five CPT soil engineering classification systems are incorporated in this effort. They include the probabilistic region estimation and fuzzy classification methods, both developed by Zhang and Tumay, the Schmertmann, the Douglas and Olsen, and the Robertson et al. methods. In the probabilistic region estimation method, a conformal transformation is used to determine the soil classification index, U, from CPT cone tip resistance and friction ratio. A statistical correlation is established between U and the compositional soil type given by the Unified Soil Classification System (USCS). The soil classification index, U, provides a soil profile over depth with the probability of belonging to different soil types, which more realistically and continuously reflects the in-situ soil characterization, which includes the spatial variation of soil types. The CPT fuzzy classification on the other hand emphasizes the certainty of soil behavior. The advantage of combining these two classification methods is realized through implementing them into visual basic software with three other CPT soil classification methods for friendly use by geotechnical engineers. Three sites in Louisiana were selected for this study. For each site, CPT tests and the corresponding soil boring results were correlated. The soil classification results obtained using the probabilistic region estimation and fuzzy classification methods are cross-correlated with conventional soil classification from borings logs and three other established CPT soil classification methods.

• 한국재료학회지
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• 제21권10호
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• pp.550-555
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• 2011

A high-quality CIGS film with a selenization process needs to be developed for low-cost and large-scale production. In this study, we used $Cu_2In_3$, CuGa and $Cu_2Se$ sputter targets for the deposition of a precursor. The precursor deposited by sputtering was selenized in Se vapor. The precursor layer deposited by the co-sputtering of $Cu_2In_3$, CuGa and $Cu_2Se$ showed a uniform distribution of Cu, In, Ga, and Se throughout the layer with Cu, In, CuIn, CuGa and $Cu_2Se$ phases. After selenization at $550^{\circ}C$ for 30 min, the CIGS film showed a double-layer microstructure with a large-grained top layer and a small-grained bottom layer. In the AES depth profile, In was found to have accumulated near the surface while Cu had accumulated in the middle of the CIGS film. By adding a Cu-In-Ga interlayer between the co-sputtered precursor layer and the Mo film and adding a thin $Cu_2Se$ layer onto the co-sputtered precursor layer, large CIGS grains throughout the film were produced. However, the Cu accumulated in the middle of CIGS film in this case as well. By supplying In, Ga and Se to the CIGS film, a uniform distribution of Cu, In, Ga and Se was achieved in the middle of the CIGS film.