• Korean Journal of Materials Research
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• v.13 no.4
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• pp.266-270
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• 2003

We studied BCl$_3$ dry etching of GaAs in a planar inductively coupled plasma system. The investigated process parameters were planar ICP source power, chamber pressure, RIE chuck power and gas flow rate. The ICP source power was varied from 0 to 500 W. Chamber pressure, RIE chuck power and gas flow rate were controlled from 5 to 15 mTorr, 0 to 150 W and 10 to 40 sccm, respectively. We found that a process condition at 20 sccm $BCl_3$ 300 W ICP, 100 W RIE and 7.5 mTorr chamber pressure gave an excellent etch result. The etched GaAs feature depicted extremely smooth surface (RMS roughness < 1 nm), vertical sidewall, relatively fast etch rate (> $3000\AA$/min) and good selectivity to a photoresist (> 3 : 1). XPS study indicated a very clean surface of the material after dry etching of GaAs. We also noticed that our planar ICP source was successfully ignited both with and without RIE chuck power, which was generally not the case with a typical cylindrical ICP source, where assistance of RIE chuck power was required for turning on a plasma and maintaining it. It demonstrated that the planar ICP source could be a very versatile tool for advanced dry etching of damage-sensitive compound semiconductors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.77-80
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• 2003

MEMS(Micro Electro Mechanical System) 기술에서 실리콘 식각기술의 중요성으로 플라즈마 식각기술의 개발이 꾸준히 진행되고 있다. 이중에서 ICP(Inductive Coupled Plasma)는 기존의 증착장치에 유도결합식 플라즈마를 추가로 발생시켜 증착막의 특성을 획기적으로 개선시키는 가장 최근에 개발된 기술이며, 이용에너지를 증가시키지 않고도 이용밀도를 높이고 이용업자들에 방향성을 가할 수 있는 새로운 플라즈마 기술로, 주로 MEMS 제조공정에 응용되고 있다. 본 연구에서는 STS-ICP $ASE^{HR}$을 이용하여 식각과 증착공정을 반복하여 식각을 하는 Bosch 식각에 관하여 연구하였다 STS-ICP $ASE^{HR}$ 장비의 Platen power, Coil power 및 Process pressure에 다양한 변화를 주어 각 변수에 따른 식각속도를 관찰하였다. 각 공정별 변수를 변화시킨 결과 Platen power 12W, Coil power 500W, 식각/Passivation Cycle 6/7sec 일 경우 식각속도는 $1.2{\mu}m$/min 이었고, Sidewall profile은 $90{\pm}0.7^{\circ}$로 나타나 매우 우수한 결과를 보였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.103.1-103.1
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• 2017

Nanocrystalline HfN coatings were prepared by reactively sputtering Hf metal target with N2 gas using a magnetron sputtering system operated in DC and ICP (inductively coupled plasma) condition with various powers. The effects of ICP power, ranging from 0 to 200 W, on the coating microstructure, corrosion and mechanical properties were systematically investigated with FE-SEM, AFM, potentiostat and nanoindentation. The results show that ICP power has a significant influence on coating microstructure and mechanical properties of HfN coatings. With the increasing of ICP power, coating microstructure evolves from the columnar structure of DC process to a highly dense one. Average grain size and nano hardness of HfN coatings were also investigated with increasing ICP powers.

• Journal of the Korean institute of surface engineering
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• v.45 no.4
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• pp.168-173
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• 2012

A real-time monitoring of an immersed antenna type inductively coupled plasma (ICP) was done with optical emission spectroscopy (OES) to check the reports that sputtered atom density is decreasing as the ICP power is increased. At 10 mTorr pressure of Ar, Mg was sputtered by a bipolar pulsed power supply into 2 MHz ICP which has an insulator covered 2.5 turn antenna. Emitted light was collected in two different positions: above the target and inside the ICP region. With 100 W of Mg sputtering power, the intensities of Mg I (285.06 nm), Mg II (279.48 nm), Ar I (420.1 nm) were increased constantly with ICP power from 100 W to 600 W. At 500 W, the intensity of $Mg^+$ exceeded that of Mg under PID controlled discharge voltage of 180 V. The ratio of Mg II/Mg I was increased from 0.45 to 2.71 approximately 6 times.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.443-451
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• 2015

In photogrammetry, GCPs (Ground Control Points) have traditionally been used to determine EOPs (Exterior Orientation Parameters) and to produce DEM (Digital Elevation Model). The existing DEM can be used as GCPs, where the observer’s approach is a difficult area, because it is very restrictive to survey in the field. For this, DEM matching should be performed. This study proposed the fusion method using ICP (Iterative Closest Point) and RT (proposed method by Rosenholm and Torlegard, 1988) in order to improve accuracy of the DEM matching. The proposed method was compared to the ICP method to evaluate its usefulness. Pseudo reference DEM with resolution 10m, and modified DEM (random-numbers are added from 0 to 2 at height; scale is 0.9; translation is 100 meters in 3-D axes; rotation is from 10° to 50° from the reference DEM) were used in the experiment. The results proposed accuracy was highest in the matching and absolute orientation. In the case of ICP, according to rotation of the modified DEM being increased, absolute orientation error is increased, while the proposed method generally showed consistent results without increasing the error. The proposed method would be applied to matching when the DEM is modified up to 30° rotation, compared to the reference DEM, based on the results of experiments. In addition when we use Drone, this method can be utilized to identify EOPs or detect 3-D surface deformation from the existing DEM of the inaccessible area.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1038-1045
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• 2006

A series of experiments was conducted to test the compatibilities of two different techniques to determine elemental concentrations by INAA and ICP-MS based on both the NIST SRM 2783(air particulate on filter media) and the field samples for PM10. For NIST SRM the results of INAA were more accurate and precise for all target elements than those of ICP-MS. The comparative data set for PM10 samples collected in an industrial complex area showed that mean of concentration ratio, derived for the two different methods such as C(INNA/ICP-MS), were distinguished from each other: (1) Ba, Cu, K Mg, Na, and Sb: $0.9{\sim}1.1$; (2) Al, Co, Fe, and Mn: $0.8{\sim}1.2$; and (3) Se, Ti, and Zn: >1.3. When the results obtained from both methods were evaluated in terms of regression analysis, paired t-test, and Wilcoxon signed-rank test, the results of many elements determined from PM10 samples(such as Al, Ba, Co, Cu, Fe, K, Mn, Nd, and Sb) exhibited a fairly good agreement between the two methods, despite a wide range of variation.

• Journal of Environmental Health Sciences
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• v.47 no.1
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• pp.64-77
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• 2021

Objective: Biological monitoring of trace elements in human blood samples has become an important indicator of the health environment. The purpose of this study was to detect and evaluate multiple metal items in blood samples based on ICP-MS, to perform comparative evaluation with the existing analysis method, and to develop and verify a new method. Methods: 100 μL of whole blood from 80 healthy subjects was used to analyze ten metals (Sb, tAs, Cd, Pb, Mn, Hg, Mo, Ni, Se, Tl) using ICP-MS. Verification of the analysis method included calculation of linearity, accuracy, precision and detection limits. In addition, a comparative test with the conventional graphite furnace atomic absorption spectroscopy (GF-AAS) method was performed. In the case of Pb, Cd, and Hg in whole blood, cross-analysis between Pb, Cd, and Hg analysis methods was performed to confirm the difference between the existing method and the new method (ICP-MS). Results: The coefficient of determination (R2) was 0.999 or higher in seven items and 0.995 or higher in three items. The Pb result showed that Pearson's correlation coefficient was very high at 0.983, and the intraclass correlation coefficient was 0.966. The Cd result showed that Pearson's correlation coefficient was 0.917 between the existing method and the new analysis concentration value. Its intraclass correlation coefficient was 0.960, and there was no significant difference between the two groups. Hg had a low correlation at 0.687, and the intraclass correlation coefficient was 0.761, which was lower than that of Pb and Cd. The intra-day and inter-day accuracy of Pd and Cd were satisfactory, but Hg did not meet the criteria for both accuracy and precision when compared with the conventional analysis method. Conclusion: This study can be meaningful in that it proposes a more efficient and feasible analysis method by verifying a blood heavy metal concentration experiment using multiple simultaneous analyses. All samples were processed and analyzed using the new ICP-MS. It was confirmed that the agreement between the two methods was very high, with the agreement between the current and new methods being 0.769 to 0.998. This study proposes an efficient simultaneous methodology capable of analyzing multiple elements with small samples. In the future, studies of various applications and the reliability of ICP-MS analysis methods are required, and research on the verification of accurate, precise, and continuous analysis methods is required.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.71-75
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• 2005

$La_{0.5}Ca_{0.5}MnO_3$ colossal magnetoresistance (CMR) powders and pellets were synthesized by sol-gel process. The structural changes were investigated by FT-IR, CP/MAS $^{13}C$ solid state NMR spectroscopy and XRD. The particle characterization, microstructure of sintered samples, and cation composition of gel powders were studied by FE-SEM/EDS, TEM and ICP-AES. The structure refinement reveals that $La_{0.5}Ca_{0.5}MnO_3$ has orthorhombic, perovskite type unit cell. The magnetic characterizations were identified through measurement of magnetic moment by VSM.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.10
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• pp.4761-4767
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• 2016

Objective: The use of Shamma (smokeless tobacco) by certain groups is giving rise to health problems, including cancer, in parts of Saudi Arabia. Our objective was to determine metals levels in Shamma using inductively coupled plasma mass spectrometry (ICP-MS). Methods: Thirty-three samples of Shamma (smokeless tobacco) were collected, comprising four types: brown Shamma (n = 14.0), red Shamma (n = 9.0), white Shamma (n = 4.0), and yellow Shamma (n = 6.0). All samples were collected randomly from Shamma users in the city of Najran. Levels of 11 elements (Al, As, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, and Zn) were determined by ICP-MS. Results: A mixed standard (20 ppb) of all elements was used for quality control, and average recoveries ranged from 74.7% to 112.2%. The highest average concentrations were found in the following order: Al ($598.8-812.2{\mu}g/g$), Mn ($51.0-80.6{\mu}g/g$), and Ni ($23.2-53.3{\mu}g/g$) in all four Shamma types. The lowest concentrations were for As ($0.7-1.0{\mu}g/g$) and Cd ($0.0-0.06{\mu}g/g$). Conclusions: The colour of each Shamma type reflects additives mixed into the tobacco. Cr and Cu were showed significant differences (P < 0.05) among Shamma types. Moreover, Pb levels are higher in red and yellow Shamma, which could be due to use (PbCrO4) as yellow colouring agent and lead tetroxide, Pb3O4 as a red colouring agent. The findings from this study can be used to raise public awareness about the safety and health effects of Shamma, which is clearly a source of oral exposure to metals.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.237-237
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• 2011

본 연구에서는 중성입자빔과 일반적인 ICP 플라즈마를 이용하여 성장시킨 SiON 박막의 물리적 특성 및 전기적 특성을 비교하여 분석하였다. 중성입자빔 및 ICP 플라즈마를 이용하여 기판 온도 400$^{\circ}C$ 조건에서 공정 시간에 따라 각각의 SiON 박막을 성장시켰으며 SiON 박막에 metal insulator semiconductor(MIS) 구조를 만들어 capacitance-voltage (C-V), current-voltage (I-V) 특성, 박막 두께 및 박막 내의 질소 분포 등을 비교 분석하였다. 기판 온도 400$^{\circ}C$ 조건에서 형성시킨 중성입자빔 및 플라즈마-SiON 박막의 두께는 6.0~10.0 nm, 굴절률 (n)은 1.5~1.8이며, 유전 상수는 4.2~5.0이다. 중성입자빔 SiON 박막의 절연파괴 전압은 약 14 MV/cm 이며, 플라즈마-SiON 박막의 절연파괴전압은 약 9~11 MV/cm 수준으로 중성입자빔-SiON 박막에 비하여 낮은 수준이다. 따라서 중성입자빔을 이용하여 400$^{\circ}C$에서 하전 입자에 의한 손상이 없는 양질의 SiON 박막을 형성시킬 수 있었다.