• Korean Chemical Engineering Research
• /
• 제43권4호
• /
• pp.531-536
• /
• 2005

포토리지스트 마스크로 패턴된 CoTb 및 CoZrNb 자성 박막에 대한 유도 결합 플라즈마 반응성 이온 식각이 $Cl_2/Ar$와 $C_2F_6/Ar$ 가스를 이용하여 진행되었고 식각 속도와 식각 프로파일 측면에서 조사되었다. $Cl_2$와 $C_2F_6$ 가스의 농도가 증가함에 따라서 자성 박막들의 식각 속도는 감소하였고 식각 경사는 낮아졌다. 자성 박막들의 식각 가스로서 $Cl_2/Ar$이 빠른 식각 속도와 가파른 식각 경사를 얻는데 있어서 $C_2F_6/Ar$ 보다 더 효과적이었다. Coil rf power의 증가는 플라즈마 내의 Ar 이온과 라디칼의 밀도를 증가시키고 dc bias voltage의 증가는 기판으로 스퍼터되는 Ar 이온의 에너지를 증가시키기 때문에 coil rf power와 dc bias voltage가 증가할수록 식각 속도와 식각 경사는 증가하였지만 패턴의 측면에서 재증착이 일어났다. 자성 박막들의 적층으로 형성된 magnetic tunnel junction stack에 고밀도 플라즈마 반응성 이온 식각을 적용하여, 높은 식각 경사와 재증착이 없는 깨끗한 식각 프로파일을 얻었다.

• KSBB Journal
• /
• 제25권1호
• /
• pp.85-90
• /
• 2010

An ion selective microelectrode (ISME) was fabricated to measure concentrations of ammonium (${NH_4}^+$-N) and nitrate (${NO_3}^-$-N) according to the depth of nitrifying biofilm. The limits of detectability and validity of results were investigated to evaluate the ISME. The electromotive force (EMF) was directly proportional to the ion concentration, and average detection limits of ${NH_4}^+$ and ${NO_3}^-$ ISME were $10^{-5.14}$ and $10^{-5.18}$ M, respectively. The concentrations of ${NH_4}^+ $-N and ${NO_3}^-$-N in various depths on the nitrifying biofilm were measured by the ISME. When a modified Ludzack-Ettinger (MLE) process was operated at an HRT of 6 h, concentration gradients of ${NH_4}^+$-N in the bulk solution and biofilm at depths of $100\;{\mu}m$ decreased by $70\;{\mu}M$, while ${NO_3}^-$-N increased by $101\;{\mu}M$ and remained constant thereafter. At an HRT of 4 h, concentration gradients of ${NH_4}^+$-N at depths of $500\;{\mu}m$ decreased by $160\;{\mu}M$ and ${NO_3}^-$-N increased by $162;{\mu}M$ and remained constant thereafter. As HRT decreased, the concentration gradients of ${NH_4}^+$-N and ${NO_3}^-$-N between bulk solution and biofilm was higher due to the increase of nitrogen load. Also, the concentration gradients of the ${NH_4}^+$-N and ${NO_3}^-$-N of biofilm in the second aerobic tank were lower than those of the first aerobic tank, suggesting differences of nitrogen load and concentrations of DO between the first and second aerobic tank.

• Mass Spectrometry Letters
• /
• 제15권2호
• /
• pp.95-106
• /
• 2024

Taraxacum coreanum, known as the native Korean white dandelion, has been historically used in traditional medicine due to its various therapeutic properties. However, the specific benefits and mechanisms of white dandelion in alleviating particular symptoms or diseases remain uncertain due to the complexity of its phytochemical profile. In this study, we aimed to elucidate the phytochemical profiles of methanolic extracts of different parts of the white dandelion (flower, leaf, stem, and root) using hybrid ion-mobility Q-TOF MS. Using the trapped ion mobility-based PASEF technique, 3715 and 2114 molecular features with MS2 fragments were obtained in positive and negative ion modes, respectively, and then a total of 360 and 156 phytochemical compounds were annotated by matching with a reference spectral library in positive and negative ion modes, respectively. Subsequent feature-based molecular networking analysis revealed the phytochemical differences across the four different parts of the white dandelion. Our findings indicated that the methanolic extracts contained various bioactive compounds, including lipids, flavonoids, phenolic acids, and sesquiterpenes. In particular, lipids such as linoleic acids, lysophosphatidylcholines, and sesquiterpenoids were predominantly present in the leaf, while flavonoid glycosides and lysophosphoethanolamines were notably enriched in the flower. An assessment of the total phenolic content (TPC) and total flavonoid content (TFC) of the methanolic extracts revealed that the majority of phytochemicals were concentrated in the flower. Interestingly, despite the root extract displaying the lowest TPC and TFC values, it exhibited the highest radical scavenging rate when normalized to TPC and TFC, suggesting a potent antioxidant effect. These findings and further investigations into the biological activities and medicinal potential of the identified compounds, particularly those exclusive to specific plant parts, may contribute to the development of novel therapeutic agents derived from white dandelion.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.289.1-289.1
• /
• 2016

Germanium (Ge) with higher carrier mobility and a lower crystallization temperature has been considered as the channel material of thin-film transistors for display applications. Various methods were studied for crystallizaion of poly-Ge from amorphous Ge at low temperature. Especially Metal induced crystalliazation (MIC) process was widely studied because low process cost. In this paper, we investigate copper diffusion process of different thick (70 nm, 350 nm) poly-Ge film obtained by MIC process at various temperatures (250, 300, and $350^{\circ}C$) through atomic force microscopy (AFM), Raman spectroscopy, and secondary ion mass spectroscopy (SIMS) measurement. Crystallization completeness and grain size was similar in all the conditions. Copper diffusion profile of 370 nm poly-Ge film show simirly results regardless of process temperature. However, copper diffusion profile of 70 nm poly-Ge film show different results by process temperature.

• E2M - 전기 전자와 첨단 소재
• /
• 제10권9호
• /
• pp.881-888
• /
• 1997

This study demonstrats the profiles of phosphorus ions in silicon by MeV implantation(1∼3 MeV). Implanted profiles could be measured by SIMS(Cameca 4f) and compared with simulation results(TRIM program and analytical description method only using on Pearson function). The experimental result in the peak concentration region has a little bit deviation from simulation data. By RBS and Channeling measurements the defect distribution of implanted samples could be measured and spectrum are calibrated depth with RUMP simulation By XTEM measurement the thickness of defect zone also could be measured. Finally thermal annealing for the electrical activation of implanted ions carried out by RTA(rapid thermal annealing). The concentration-depth profiles after heat treatment was measured by SR(spreading resistance)-method.

• Applied Science and Convergence Technology
• /
• 제23권4호
• /
• pp.179-186
• /
• 2014

Fluid model based numerical simulation was carried out for an inductively coupled plasma assisted sputter deposition system. Power absorption, electron temperature and density distribution was modeled with drift diffusion approximation. Effect of an electrically conducting substrate was analyzed and showed confined plasma below the substrate. Part of the plasma was leaked around the substrate edge. Comparison between the quasi-neutrality based compact model and Poisson equation resolved model showed more broadened profile in inductively coupled plasma power absorption than quasi-neutrality case, but very similar Ar ion number density profile. Electric potential was calculated to be in the range of 50 V between a Cr rod source and a conductive substrate. A new model including Cr sputtering by Ar+was developed and used in simulating Cr deposition process. Cr was modeled to be ionized by direct electron impact and showed narrower distribution than Ar ions.

• Bulletin of the Korean Chemical Society
• /
• 제10권6호
• /
• pp.585-591
• /
• 1989

The effects of the charged metal on the overall electrostatic potential profiles and the capacitances of the electrical double layer are brought out. A model with a simplified jellium and a point-charged electrolyte is utilized in the present calculations. Electrons are assumed not to penetrate electrode surface due to a strong screening of electrolyte at the interface. Electron density functions and ion density functions are obtained, which are also based upon the Poisson equation and Boltzmann equation on either side of the interface. A complete potential profile starting from bulk electrode and ending at bulk electrolyte is obtained by connecting the two potential profiles (one inside the metal electrode, the other inside the electrolyte) with proper boundary conditions. In spite of the simplicity of the model, the present model reveals the importance of the effect of the charged metal on the electrostatic potential profile and the electrical double layer capacitances. The results are discussed and compared with the predictions by Gouy Chapman theory.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.275-275
• /
• 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
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.232-232
• /
• 2010

정보화 산업의 발달은 DRAM, flash memory 등을 포함한 기존의 반도체 메모리 소자를 대체할 수 있는 차세대 메모리 소자에 대한 개발을 요구하고 있다. 특히 magnetic random access memory (MRAM)는 SRAM과 대등한 고속화 그리고 DRAM 보다 높은 기록 밀도가 가능하고 낮은 동작 전압과 소비전력 때문에 대표적인 차세대 비휘발성 메모리로 주목받고 있다. 또한 MRAM소자의 고집적화를 위해서 우수한 프로파일을 갖고 재증착이 없는 나노미터 크기의 magnetic tunnel junction (MTJ) stack의 건식 식각에 대한 연구가 선행되어야 한다. 본 연구에서는 고밀도 반응성 이온 식각법(Inductively coupled plasma reactive ion etching; ICPRIE)을 이용하여 재증착이 없이 우수한 식각 profile을 갖는 CoFeB과 IrMn 박막을 형성하고자 하였다. Photoresist(PR) 및 Ti 박막의 두 가지 마스크를 이용하여 HBr/Ar, HBr/$O_2$/Ar 식각 가스들의 농도를 변화시키면서 CoFeB과 IrMn 박막의 식각 특성들이 조사되었다. 자성 박막과 동일한 조건에 대하여 hard mask로서 Ti가 식각되었다. 좋은 조건을 얻기 위해 HBr/Ar 식각 가스를 이용 식각할 때 pressure, bias voltage, rf power를 변화시켰고 식각조건에서 Ti 하드마스크에 대한 자성 박막들의 selectivity를 조사하고 식각 profile을 관찰하였다. 식각 속도를 구하기 위해 alpha step(Tencor P-1)이 사용되었고 또한 field emission scanning electron microscopy(FESEM)를 이용하여 식각 profile을 관찰함으로써 최적의 식각 가스와 식각 조건을 찾고자 하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.244.2-244.2
• /
• 2013

Contact Pattern을 Plasma Etching을 통해 Pattering 공정을 진행함에 있어서 Plasma 내에 존재하는 High Energy Ion 들의 Bombardment 에 의해, Contact Bottom 의 Silicon Lattice Atom 들은 Physical 한 Damage를 받아 Electron 의 흐름을 방해하게 되어, Resistance를 증가시키게 된다. 또한 Etchant 로 사용되는 Fluorine 과 Chlorine Atom 들은, Contact Bottom 에 Contamination 으로 작용하게 되어, 후속 Contact 공정을 진행하면서 증착되는 Ti 나 Co Layer 와 Si 이 반응하는 것을 방해하여 Ohmic Contact을 형성하기 위한 Silicide Layer를 형성하지 못하도록 만든다. High Aspect Ratio Contact (HARC) Etching 을 진행하면서 Contact Profile을 Vertical 하게 형성하기 위하여 Bias Power를 증가하여 사용하게 되는데, 이로부터 Contact Bottom에서 발생하는 Etchant 로 인한 Damage 는 더욱 더 증가하게 된다. 이 Damage Layer를 추가적인 Secondary Damage 없이 제거하기 위하여 본 연구에서는 원자층 식각방법(Atomic Layer Etching Technique)을 사용하였다. 실험에 사용된 원자층 식각방법을 이용하여, Damage 가 발생한 Si Layer를 Secondary Damage 없이 효과적으로 Control 하여 제거할 수 있음을 확인하였으며, 30 nm Deep Contact Bottom 에서 Damage 가 제거될 수 있음을 확인하였다. XPS 와 Depth SIMS Data를 이용하여 상기 실험 결과를 확인하였으며, SEM Profile 분석을 통하여, Damage 제거 결과 및 Profile 변화 여부를 확인하였으며, 4 Point Prove 결과를 통하여 결과적으로 Resistance 가 개선되는 결과를 얻을 수 있었다.