• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.175.2-175.2
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• 2015

이 연구는 nano-indenter를 중심으로 박막의 nano-electrotribology 분석 연구로 Hafnium Nitride (HfN) 박막의 열처리 시 열적안정성에 대한 연구를 진행하였다. HfN 박막은 Copper (Cu)와 Silicon (Si)의 계면 확산방지막으로 사용될 수 있는 박막으로 현재 많은 연구소에서 다양한 연구가 진행되고 있다. HfN 박막은 Si (100)기판 위에 rf magnetron sputter로 증착되었다. 증착 시 Ar, $N_2$ 가스유량을 총 40 sccm 사용하였고 증착 후 HfN 박막을 질소분위기 furnace에서 500, $700^{\circ}C$로 각각 30분 동안 열처리 하였다. 열처리 전 후의 시료를 nano-indenter를 이용하여 nano-electrotribology 분석을 실시하였다. Nano-indenter 측정결과 열처리 전 HfN 박막 시료의 표면강도는 39.68 GPa였고 500oC 열처리 후 31.31 GPa로 감소하였다. 그러나 $700^{\circ}C$ 열처리 시 표면강도가 37.89 GPa로 다시 증가하였다. 탄성계수 측정결과도 이와 같은 경향을 나타내었는데, $500^{\circ}C$ 열처리 전 후 탄성계수가 258.99 GPa에서 201.88 GPa로 감소하였고 $700^{\circ}C$ 열처리 시 247.55 GPa로 다시 증가하였다. 이는 $500^{\circ}C$ 열처리하였을 때 박막 내에 흡착되었던 $N_2$ 가스가 빠져나가며 tensile stress가 발생하여 박막의 표면강도 감소를 유발했고 $700^{\circ}C$ 열처리 시 다시 박막 표면이 안정화되었기 때문으로 생각된다. 이를 통해 열처리 온도 변화에 의한 질소효과가 나타나 HfN 박막 표면의 물성이 달라지는 것을 확인하였다.

• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.183-194
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• 1992

Some silicon micromechanical structures useful in sensors and actuators have been fabricated by electropolishing or porous silicon formation technique by anodic reaction in HF solution. The microstructures were lightly doped single crystal silicon and the formation was isotropic independent of crystal directions. Porous silicon layer(PSL) was formed selectively in $n^{+}$ region of $n^{+}/n$ silicon structure by anodic reaction in concentrated HF(20-48%) solution. Characteristics of the formed PSL were investigated along with change of the reaction voltage, HF concentration and the reaction time. PSL was formed only in $n^{+}$ region. The porosity of the PSL was decreased with the increase of HF concentration and independent of reaction voltage. For the case of $n/n^{+}/n$ structures, the etched surface of silicon was fairly smooth and a cusp was not found. The thickness of the microstructures was the same as that of the epitaxial n-Si layer and good uniformity. We have fabricated acceleration sensors by anodic reaction in HF solution(5 wt%) and planar technology. The process was compatible with conventional It fabrication technique. Various micromechanical structures, such as rotors of motor, gears and linear actuator, were also fabricated by the technique and examined by SEM photographs.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.185-190
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• 2003

고유전물질인 $HfO_2$ 극박막에 사용될 TaN metal 전극에 대한 특성에 대한 연구를 하였다. 고유전물질인 $HfO_2$는 4" p-type wafer를 SCI cleaning후 ALD(atomic layer deposition)을 통해 $50\AA$를 증착하였다. Ff source는 TEMAH를 이용하였으며 Oxygen source는 $H_2O$를 이용하였다. 이렇게 증착한 $HfO_2$ 극박막에 Ta target을 이용하여 질소 가스를 Ar가스에 첨가하여 reactive sputtering을 통해서 TaN 전극을 증착하였다. TaN 박막의 증착두께는 a--step과 TEM을 통해서 확인하였으며 면저항은 four point probe를 이용하여 측정하였다. 이렇게 증착된 $HfO_2/TaN$구조에 대한 전기적 특성을 측정하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.103.2-103.2
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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 ABPP (asymmetric bipolar pulsed plasma) condition with various duties and frequencies. The effects of duty and frequency, ranging from 75 to 100 % and 5 to 50 kHz, on the coating microstructure, crystallographic and mechanical properties were systematically investigated with FE-SEM, AFM, XRD and nanoindentation. The results show that pulsed plasma has a significant influence on coating microstructure and mechanical properties of HfN coatings. Coating microstructure evolves from the columnar structure to a highly dense one as duty decreases. Average grain size and nano hardness of HfN coatings were also investigated with various pulsed conditions.

• 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.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.39-40
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• 1998

Diffusion barrier characteristics of hf(C,N) thin films for Cu metalliztion was investgated. Hf(C,N) thin films were depposited on Si(100) suvstrates by ppulsed D. C pplasma enhanced metal-organic chemical vappor depposition (ppE-MOCVD) using Tetrakis diethyl amido hafnium (Hf[NC2H5)2]4 : TDEAHf) and N2 as pprecursors. X-ray diffraction analyses sheet resistance measurment and Rutherford backscattering sppectroscoppy analyses revealed that HF(C,N) films pprevent diffusion of Cu fairly well upp to $600^{\circ}C$. At $700^{\circ}C$ however Hf(C,N) films allowed a significant diffusion of Cu into the Si substrate.

• Journal of Life Science
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• v.21 no.6
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• pp.829-837
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• 2011

The purpose of this study was to investigate the effects of ethanol extracts from red pepper seeds on cholesterol adsorption capacity and UDP-glucuronyl transferase activity. In vitro cholesterol adsorption capacity of 2%, 5% and 10% ethanol extracts from red pepper seed groups were significantly higher than that of the control group. Sprague-Dawley strain male rats weighing $100{\pm}10$ g were randomly assigned to one normal diet N group and experimental groups fed high fat and high cholesterol diet, which were divided into HF (0.0%), HEA (0.1%), HEB (0.2%), and HEC (0.5%) groups according to the amount of ethanol extracts from red pepper seeds added to their basal diet. The body weight gain in the HF group was higher than that in the N group, and those in the HEA, HEB and HEC groups were lower than that in the HF group However, there were no statistically significant differences among the all the groups. The hepatic triglyceride and total cholesterol contents in the N group was significantly lower than that in the HF group, and those in the HEA, HEB and HEC groups were lower than that in the HF group. The hepatic UDP-glucuronyl transferase activity in the N group was lower than that of the HF group and those in the HEA, HEB and HEC groups were lower than that of the HF group. The serum total cholesterol and triglyceride contents of the HF group were significantly higher than that of the N group, and those of the HEA, HEB and HEC groups were lower than that of the HF group. The serum HDL-cholesterol contents in all groups supplemented with the ethanol extracts from red pepper seeds were significantly higher than that of the HF group. The serum LDL-cholesterol contents of the HF group were significantly higher than that of the N group, and those of the HEA, HEB and HEC groups were lower than that of the HF group. The fecal total cholesterol contents were significantly higher in the HF group compared to the N group, and those of the HEB and HEC groups were lower than that of the HF group. The fecal triglyceride contents in the N group was higher than that of the HF group, and those of the HEA, HEB and HEC groups were lower than that of the HF group. This study suggested that the ethanol extracts from red pepper seeds have powerful health benefits by the UDP-glucuronyl transferase activity and lipid metabolism.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.216.2-216.2
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• 2013

Nano-indenter는 팁을 박막 표면으로부터 일정 깊이까지 일정한 비율로 힘을 팁에 인가하여 그에 따른 박막의 반응을 in-situ로 확인하기 위하여 고안된 장치이며, 박막은 물론 나노 구조물까지 다양한 범위에서 기계적 특성을 분석하기 위하여 사용되고 있다. 이 연구에서는 유전체 및 확산방지막으로 사용되는 Hf을 rf magnetron sputter로 증착하였으며 이때 Ar 가스와 함께 $N_2$ 가스의 혼합 비율을 다르게 하여 HfN을 증착하였다. 질소 분압에 따라 증착된 HfN 박막은 고온중에서 질소의 영향을 확인하기 위하여 $800^{\circ}C$로 질소 분위기에서 20분간 열처리하여 이후 박막의 nano-mechanical 특성을 nanoindenter를 사용하여 확인하였고 최대 압입력을 250 ${\mu}N$으로 고정하였다. 측정결과 고온 열처리후 HfN 박막은 증착시 질소 분압이 0%에서 5%로 증가함에 따라 surface hardness는 8.6 GPa에서 8.1 GPa로 elastic modulus는 123.7 GPa에서 134 GPa로 각각 변화되는 것을 확인할 수 있었다. 특히, 질소 분압이 2.5%로 증착된 HfN 박막은 열처리후 박막 표면의 물리적 특성이 깊이 방향으로 층을 이루고 있어 nano-indenter 압입시 다수의 pop-in이 나타남을 확인하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.11-14
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• 2003

[ $HfO_2$ ] thin films were deposited at $300^{\circ}C$ on p-type Si (100) substrates using $HfO_2(HfO_xN_y)$ as the precursor by plasma-enhanced chemical vapor deposition and were annealed at $300^{\circ}C$ in nitrogen plasma ambient. Compared with $HfO_2$, nitrogen plasma annealed $HfO_2$ show good chemical stability, higher crystallization temperature, lower leakage current and thermal stability. Leakage current density of nitrogen plasma annealed $HfO_2$ is approximately one order of magnitude lower than that of $HfO_2$ for the same EOT. The improvement in electrical characteristics of nitrogen plasma annealed $HfO_2$ can be explained by the better thermal stability due to nitrogen incorporation.

• Bulletin of the Korean Chemical Society
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• v.13 no.1
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• pp.11-17
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• 1992

Vibration-to-vibration energy transfer probabilities for $HF(v=n)+H_2(v=0){\to}HF(v=n-1)+H_2(v=1)$ and $DF(v=n)+D_2(v=0){\to}DF(v=n-1)+D_2(v=1)$ including both the vibration-to-vibration and translation (V-V, T) and vibration-to-vibration and rotation (V-V, R) energy transfer paths have been calculated semiclassically using a simplified collision model and Morse-type intermolecular interaction potential. The calculated results are in reasonably good agreement with those obtained by experimental studies. They also show that the transition processes for $HF(v=1-3)+H_2(v=0){\to}HF(v=0-2)+H_2(v=1)$ and $DF(v=1,\;4)+D_2(v=0){\to}DF(v=0,\;3)+D_2(v=1)$ are strongly dependent on the V-V, T path at low temperature but occur predominantly via the V-V, R path with rising temperature. The vibration-to-vibration energy transfer for $HF(v=4)+H_2(v=0){\to}HF(v=3)+H_2(v=1)$ and $DF(v=2-3)+D_2(v=0){\to}DF(v=1-2)+D_2(v=1)$ occur predominantly via V-V, R path and V-V, T path through whole temperatures, respectively.