• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.701-707
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• 2004

High aspect ratio silicon structure through deep silicon etching process have become indispensable for advanced MEMS applications. In this paper, we present the results of modified Bosch process to obtain anisotropic silicon structure with conventional Inductively Coupled Plasma (ICP) etcher instead of the expensive Bosch process systems. In modified Bosch process, etching step ($SFsub6$) / sidewall passivation ($Csub4Fsub8$) step time is much longer than commercialized Bosch scheme and process transition time is introduced between process steps to improve gas switching and RF power delivery efficiency. To optimize process parameters, etching ($SFsub6$) / sidewall passivation ($Csub4Fsub8$) time and ion energy effects on etching profile was investigated. Etch profile strongly depends on the period of etch / passivation and ion energy. Furthermore, substrate temperature during etching process was found to be an important parameter determining etching profile. Test structures with different pattern size have been etched for the comparison of the aspect ratio dependent etch rate and the formation of silicon grass. At optimized process condition, micropatterns etched with modified Bosch process showed nearly vertical sidewall and no silicon grass formation with etch rate of 1.2 ${\mu}{\textrm}{m}$/ min and the size of scallop of 250 nm.

• 한국염색가공학회지
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• 제16권5호
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• pp.28-34
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• 2004

The polarizing film application exploits the unique physicochemical properties between PVA(Poly vinyl alcohol) film and CTA(Cellulose triacetate) film. However, hardly any research was aimed at improving the adhesion characteristics of the CTA film by radio frequency(RF) plasma treatment at argon(Ar) gaseous state. In this report, we deal with surface treatment technology for protective CTA film developed specifically for high adhesion applications. After Ar plasma, surface of the films is analyzed by atomic force microscopy(AFM), roughness parameter and peel strength. Furthermore, the wetting properties of the CTA film were studied by contact angle analysis. Results obtained for CTA films treated with a glow discharge showed that this technique is sensitive to newly created physical functions. The roughness and peel strength value increased with an increase in treatment time for initial treatment, but showed decreasing trend for continuous treatment time. The result of contact angle measurement refer that the hydrophilicity of surface was increased. AFM studies indicated that no considerable change of surface morphology occurred up to 3 minutes of treatment time, but a considerable uneven of surface structure resulted from treating time after 5 minutes.

• 반도체디스플레이기술학회지
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• 제21권2호
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• pp.38-44
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• 2022

Plasma density in semiconductor fabrication equipment becomes higher to achieve the improved the throughput of the process, but the increase of surface corrosion of the ceramic coated chamber wall has been observed by the increased plasma density. Plasma chamber wall coating with aerosol deposition prefer to be firm and uniform to prevent the potential creation of particle inside the chamber from the deformation of the coating materials, and the aerosol discharge nozzle is a good control factor for the deposited coating condition. In this paper, we investigated the design of the nozzle of the aerosol deposition to form a high-quality coating film. Computational fluid dynamics (CFD) study was employed to minimize boundary layer effect and shock wave. The degree of expansion, and design of simulation approach was applied to found out the relationship between the divergence angle and nozzle length as the key parameter for the nozzle design. We found that the trade-off tendency between divergence angle and nozzle length through simulation and quantitative analysis, and present the direction of nozzle design that can improve the uniformity of chamber wall coating.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(2)
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• pp.216-221
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• 1998

A study on induction plasma deposition with ceramic materials, yttria-stabilized-zirconia ZrO$_2$-Y$_2$O$_3$ (m.p 264O $^{\circ}C$), was conducted with a view developing a new method for nuclear fuel fabrication Before making dense pellets more than 96％TD., the spraying condition was optimized through the process parameters, such as chamber pressure, plasma plate power powder spraying distance, sheath gas composition, probe position, particle size and powders different morphology. The results with a 5mm thick deposit on rectangular planar graphite substrates showed a 97.11％ theoretical density when the sheath gas flow rate was Ar/H$_2$120/20 l/min, probe position 8cm, particle size -75 ${\mu}{\textrm}{m}$ and spraying distance 22cm by AMDRY146 powder. The degree of influence of the main effects on density were powder morphology. particle size, sheath gas composition, plate power and spraying distance, in that order. Among the two parameter interactions, the sheath gas composition and chamber pressure affects density greatly. By using the multi-pellets mold wheel type, the pellet density did not exceed 94%T.D., owing to the spraying angle.

• 한국융합학회논문지
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• 제11권10호
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• pp.1-7
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• 2020

뉴로모픽 소자 초기 단계인 저항 변화형 메모리 소자의 제작 공정으로, 진공 공정의 연속성을 유지하였고, 고집적, 고신뢰성을 보장하는 뉴로모픽 컴퓨팅을 위한 저항 변화 메모리 소자 제작 및 공정 기술에 적합한 플라즈마 모듈을 적용하였다. 플라즈마 모듈을 적용한 저항메모리(ReRAM) 소자의 제작과 연구는 ReRAM 소자 기반의 TiO₂/TiOx 산화물박막의 제작방법과 소재의 변화를 통한 다양한 실험을 통하여 완성되었다. XRD를 이용하여 rutile결정을 측정하였고, 반도체 파라미터 측정기로 저항 메모리의 HRS : LRS 비율이 2.99 × 10³ 이상이고, 구동 전압 측정이 0.3 V이하에서 구동이 가능한 저항 변화형 메모리 소자의 제작을 확인 하였다. 산소 플라즈마 모듈을 적용한 뉴로모픽 저항메모리 제작과 TiOx 박막을 증착하여 성능을 확인하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제1권1호
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• pp.79-82
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• 1997

The present study was aimed to explore an interaction between endothelium-derived nitric oxide (NO) and atrial natriuretic peptide (ANP) systems in normotensive and hypertensive states. Rats were made two-kidney, one clip (2K1C) hypertensive and supplemented with either $N^G-nitro-L-arginine$ methyl ester (L-NAME, 5 mg/100 ml drinking water) or L-arginine hydrochloride (400 mg/100 ml drinking water). One group supplied with normal tap water served as control. Sham-clipped rats were also divided into the L-NAME, L-arginine, and control groups. The plasma levels and atrial contents of ANP were determined at day 28 following clipping the renal artery. In 2K1C rats, the plasma level of ANP was higher and the atrial content was lower than in the sham-clipped control. L-Arginine increased the atrial content of ANP in association with a decreased plasma ANP, whereas L-NAME significantly affected neither parameter. The increase of blood pressure in 2K1C rats was not affected by L-arginine or L-NAME. In sham-clipped rats, the plasma level of ANP was significantly increased by L-NAME along with an increase in blood pressure. On the contrary, L-arginine did not affect the blood pressure or plasma ANP. The atrial content of ANP was significantly altered neither by L-arginine nor by L-NAME. These results suggest that NO plays a tonic inhibitory role on the ANP release with concomitant increases of the atrial tissue content. In addition, hypertension is suggested to modify the release and tissue storage of ANP.

• Journal of Photoscience
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• 제4권2호
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• pp.41-48
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• 1997

The plasma membrane and microsomes, isolated from the cells treated with hematoporphyrm derivative (HpD) for 1 and 24 h, accumulated the aggregated porphyrin. The quantity of aggregated porphyrin was same in the plasma membrane and microsomes after isolating them from cells treated with HpD for 1 h whereas the microsomes accumulated higher quantity of aggregated porphyrin when cells were treated with HpD for 24 h. Photodynamic action of aggregated porphyrin on plasma membrane and microsomes was investigated using lipid specific fluorescent probes: 1,6-diphenyl-1,3,5-hexatrine (DPH) and 1-(4-trimethylammonium), 6-diphenyl-1,3,5-hexatrine(TMA-DPH). The time dependent anisotropy of these probes in the membranes was measured and the decay of anisotropy was analyzed using wobbling in cone model. Upon irradiation both the plasma membrane and the microsomes showed an increase in the limiting anis~)tropy and order parameter and a decrease in the cone angle of the lipid probes. The increase in the limiting anisotropy was pronounced in membranes isolated from the cells treated with HpD for 24 h. Photoinduced change in the limiting anisotropy was dependent on the duration of incubation of cells with HpD before isolating the membranes. In both the membranes. the membrane core was affected more as compared to the outer leaflet. In addition to the structural changes, a decrease in Na$^+$-K$^+$-ATPase and NADPH cyt c reductase activity was also observed upon irradiation of HpD treated cells. Inhibition in NADPH cyt c reductase was more when cells were treated with HpD for 24 h, however, Na$^+$-K$^+$-ATPase activity did not depend on the duration of the treatment of cells with HpD before irradiation. Our results suggest that the extent of photoinduced perturbations in the membranes varies as a function of duration of the treatment of cells with HpD and the membrane core is more susceptible to the photodynamic action of aggregated porphyrin.

• Clinical and Experimental Reproductive Medicine
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• 제43권2호
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• pp.97-101
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• 2016

Objective: Growth hormone and its mediator, insulin-like growth factor-1 (IGF-1), have been suggested to exert gonadotropic actions in both humans and animals. The present study was conducted to assess the relationship between serum IGF-1 concentration, seminal plasma concentration, and sperm parameter abnormalities. Methods: A total of 79 men were enrolled in this study from December 2011 to July 2012 and were prospectively analyzed. Patient parameters analyzed included age, body mass index, smoking status, urological history, and fertility history. Patients were divided into four groups based on their semen parameters: normal (A, n=31), abnormal sperm motility (B, n=12), abnormal sperm morphology (C, n=20), and two or more abnormal parameters (D, n=16). Patient seminal plasma and serum IGF-1 concentrations were determined. Results: Patient baseline characteristics were not significantly different between any of the groups. The serum IGF-1 levels in groups B, C, and D were significantly lower than the levels in group A; however, the seminal plasma IGF-1 levels were not significantly different between any of the groups. Conclusion: Men with abnormal sperm parameters had significantly lower levels of serum IGF-1 compared with men with normal sperm parameters. Seminal plasma IGF-1 levels, however, did not differ significantly between the groups investigated here. Further investigations will be required to determine the exact mechanisms by which growth hormone and IGF-1 affect sperm quality.

• 한국표면공학회지
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• 제36권1호
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• pp.14-21
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• 2003

Thin films of ZrO$_2$ and TiO$_2$ were deposited on Si(100) substrates using RF magnetron sputtering technique. To study an influence of the sputtering parameters, systematic experiments were carried out in this work. XRD data show that the $ZrO_2$ films were mainly grown in the [111] orientation at the annealing temperature between 800 and $1000^{\circ}C$ while the crystal growth direction was changed to be [012] at above $1000^{\circ}C$. FT-IR spectra show that the oxygen stretching peaks become strong due to $SiO_2$ layer formation between film layers and silicon surface after annealing, and proved that a diffusion caused by either oxygen atoms of $ZrO_2$ layers or air into the interface during annealing. Different crystal growth directions were observed with the various deposition parameters such as annealing temperature, RF power magnitude, and added $O_2$ amounts. The growth rate of $TiO_2$ thin films was increased with RF power magnitude up to 150 watt, and was then decreased due to a sputtering effect. The maximum growth rate observed at 150 watt was 1500 nm/hr. Highly oriented, crack-free, stoichiometric polycrystalline $TiO_2$<110> thin film with Rutile phase was obtained after annealing at $1000^{\circ}C$ for 1 hour.

• Nuclear Engineering and Technology
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• 제14권2호
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• pp.78-85
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• 1982

정상상태의 플라즈마의 이론적 해석을 통해서 플라즈마의 회전과 동위원소 분리기로서의 적합성을 분석하였다. 이 장치는 두개의 동심원통형 전극과 이들 사이의 원통형 공동으로 구성되었으며, 축 방향으로 외부자장이 걸려 있다. 두 전극사이에 생성되는 전류밀도는 전기방전의 형태로 동위원소 혼합물로부터 플라즈마를 생성하고, 자장과 교차되어 발생하는 Lorentz힘에 의해서 플라즈마를 회전시킨다. 자기 유체역학 방정식을 바탕으로 이 계를 설명하는 두개의 연립편미분방정식을 얻었고, 네 경계조건을 사용하여 Fourier-Bessel로 표현된 이차원적 전류밀도와 속도분포의 해를 얻었다. 실제로 가능한 조건하에서 플라즈마 회전속도는 $10^4$m/sec 정도에 달하고, Hartmann수가 커짐에 따라 플라즈마회전 속도도 커진다. 이 같은 고속의 회전속도를 감안해 볼때 플라즈마 원심분리기는 기계적으로 회전되는 가스원심분리기보다 훨씬 높은 효율을 가지게 될 것이다.