• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.35-39
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• 2019

Effect of Ge₂Sb₂Te₅ (GST) chalcogen composition on plasma induced damage was investigated by using Ar ions and F radicals. Experiments were carried out with three different modes; the physical etching, the chemical etching, and the ion-enhanced chemical etching mode. For the physical etching by Ar ions, the sputtering yield was obtained according to ion bombarding energy and there was no change in GST composition ratio. In the plasma mode, the lowest etch rate was measured at the same applied power and there was also no plasma induced damage. In the ion-enhanced chemical etching conditions irradiated with high energy ions and F halogen radicals, the GST composition ratio was changed according to the density of F radicals, resulting in higher roughness of the etched surface. The change of GST composition ratio in halogen plasma is caused by the volatility difference of GST-halogen compounds with high energy ions over than the activation energy of surface reactions.

• The Journal of Advanced Prosthodontics
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• 제8권4호
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• pp.275-284
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• 2016

PURPOSE. The aim of this study was to evaluate the influence of different surface treatment methods on the microtensile bond strength of resin cement to resin nanoceramic (RNC). MATERIALS AND METHODS. RNC onlays (Lava Ultimate) (n=30) were treated using air abrasion with and without a universal adhesive, or HF etching followed by a universal adhesive with and without a silane coupling agent, or tribological silica coating with and without a universal adhesive, and divided into 6 groups. Onlays were luted with resin cement to dentin surfaces. A microtensile bond strength test was performed and evaluated by one-way ANOVA and Tukey HSD test (${\alpha}$=.05). A nanoscratch test, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy were used for micromorphologic analysis (${\alpha}$=.05). The roughness and elemental proportion were evaluated by Kruskal-Wallis test and Mann-Whitney U test. RESULTS. Tribological silica coating showed the highest roughness, followed by air abrasion and HF etching. After HF etching, the RNC surface presented a decrease in oxygen, silicon, and zirconium ratio with increasing carbon ratio. Air abrasion with universal adhesive showed the highest bond strength followed by tribological silica coating with universal adhesive. HF etching with universal adhesive showed the lowest bond strength. CONCLUSION. An improved understanding of the effect of surface treatment of RNC could enhance the durability of resin bonding when used for indirect restorations. When using RNC for restoration, effective and systemic surface roughening methods and an appropriate adhesive are required.

• 한국재료학회지
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• 제14권1호
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• pp.46-51
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• 2004

The annealing of a Cu(4.5at.% Mg)/$SiO_2$/Si structure in ambient $O_2$, at 10 mTorr, and $300-500^{\circ}C$, allows for the outdiffusion of the Mg to the Cu surface, forming a thin MgO (15 nm) layer on the surface. The surface MgO layer was patterned, and successfully served as a hard mask, for the subsequent dry etching of the underlying Mg-depleted Cu films using an $O_2$ plasma and hexafluoroacetylacetone [H(hfac)] chemistry. The resultant MgO/Cu structure, with a taper slope of about $30^{\circ}C$ shows the feasibility of the dry etching of Cu(Mg) alloy films using a surface MgO mask scheme. A dry-etched Cu(4.5at.% Mg) gate a-Si:H TFT has a field effect mobility of 0.86 $\textrm{cm}^2$/Vs, a subthreshold swing of 1.08 V/dec, and a threshold voltage of 5.7 V. A novel process for the dry etching of Cu(Mg) alloy films, which eliminates the use of a hard mask, such as Ti, and results in a reduction in the process steps is reported for the first time in this work.

• 반도체디스플레이기술학회지
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• 제13권2호
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• pp.29-35
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• 2014

In this study general solar cell production process was complemented, with research on improvement of solar cell efficiency through surface structure and thermal annealing process. Firstly, to form the pyramid structure, the saw damage removal (SDR) processed surface was undergone texturing process with reactive ion etching (RIE). Then, for the formation of smooth pyramid structure to facilitate uniform doping and electrode formation, the surface was etched with HND(HF : HNO3 : D.I. water=5 : 100 : 100) solution. Notably, due to uniform doping the leakage current decreased greatly. Also, for the enhancement and maintenance of minority carrier lifetime, antireflection coating thermal annealing was done. To maintain this increased lifetime, front electrode was formed through Au plating process without high temperature firing process. Through these changes in two processes, the leakage current effect could be decreased and furthermore, the conversion efficiency could be increased. Therefore, compared to the general solar cell with a conversion efficiency of 15.89%, production of high efficiency solar cell with a conversion efficiency of 17.24% was made possible.

• 대한소아치과학회지
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• 제30권1호
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• pp.41-46
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• 2003

공초점 레이저주사현미경(confocal laser scanning microscopy)을 이용하여 산부식시간에 따른 법랑질표면의 변화양상을 관찰하고, 접착에 필요한 표면의 양상을 얻을 수 있으면서도 법랑질의 소실을 최소화할 수 있는 산부식시간을 측정하고자, 60개의 발치된 건전대구치를 협면이 노출되도록 아크릴봉에 자가중합레진을 이용하여 매몰한 뒤, 220, 500, 800, 1000, 2000, 4000번 SiC 연마지를 이용하여 순차적으로 연마하였다. 연마된 시편을 임의로 10개씩 6개의 군으로 나누고, 37% 인산으로 10초, 20초, 30초, 40초, 50초, 60초간 산부식하고 충분한 물로 세척한 후 air syringe로 건조시킨 후, 공초점 레이저주사현미경으로 표면영상을 얻은 후 조도분석을 시행하고, 5개의 계측치(Sa, Sq, Sz, Sdr, Ra)를 통계분석한 결과, 모두 30초 산부식의 경우가 가장 높은 조도를 나타내었다. 특히 Sz의 경우 10초의 경우가 통계적으로 유의하게 낮은 값을 보였으며, 30초의 경우 통계적으로 유의하게 높은 값을 보였다(p<0.05).

• 한국재료학회지
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• 제23권2호
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• pp.116-122
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• 2013

For fabricating silicon solar cells with high conversion efficiency, texturing is one of the most effective techniques to increase short circuit current by enhancing light trapping. In this study, four different types of textures, large V-groove, large U-groove, small V-groove, and small U-groove, were prepared by a wet etching process. Silicon substrates with V-grooves were fabricated by an anisotropic etching process using a KOH solution mixed with isopropyl alcohol (IPA), and the size of the V-grooves was controlled by varying the concentration of IPA. The isotropic etching process following anisotropic etching resulted in U-grooves and the isotropic etching time was determined to obtain U-grooves with an opening angle of approximately $60^{\circ}$. The results indicated that U-grooves had a larger diffuse reflectance than V-grooves and the reflectances of small grooves was slightly higher than those of large grooves depending on the size of the grooves. Then amorphous Si:H thin film solar cells were fabricated on textured substrates to investigate the light trapping effect of textures with different shapes and sizes. Among the textures fabricated in this work, the solar cells on the substrate with small U-grooves had the largest short circuit current, 19.20 mA/$cm^2$. External quantum efficiency data also demonstrated that the small, U-shape textures are more effective for light trapping than large, V-shape textures.

• The Journal of Advanced Prosthodontics
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• 제9권2호
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• pp.77-84
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• 2017

PURPOSE. The aim of this study was to compare the surface roughness of zirconia when using Zircos E etching system (ZSAT), applying a nitric acid-hydrofluoric acid compound as a pretreatment agent, and also to compare the shear bonding strength according to different resin cements. MATERIALS AND METHODS. ZSAT, air abrasion, and tribochemical silicacoating were applied on prepared 120 zirconia specimens (10 mm in diameter, 7 mm in height) using CAD/CAM. Each 12 specimens with 4 different resin cements (Panavia F 2.0, Rely X Unicem, Superbond C&B, and Hot bond) were applied to test interfacial bond strength. The statistical analysis was performed using SAS 9.1 (SAS Institute Inc., Cary, NC, USA). The results are as follows: after application of the ZSAT on the zirconia specimens, surface roughness value after 2-hour etching was higher than those after 1- and 3-hour etching on SEM images. RESULTS. For Superbond C&B and Rely X Unicem, the specimens treated with ZSAT showed higher shear bond strength values than those treated with air abrasion and tribochemical silicacoating system. Regarding the failure mode of interface over cement and zirconia surface, Rely X Unicem and Hot bond showed cohesive failures and Panavia F 2.0 and Superbond C&B showed mixed failures. CONCLUSION. Zircos E etching system in zirconia restoration could increase its shear bond strength. However, its long term success rate and clinical application should be further evaluated.

• 대한치과보철학회지
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• 제29권3호
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• pp.75-86
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• 1991

Ion exchange strengthening is a chemical process whereby large alkali ions(such as potassium) are substituted for smaller ions(sodium) within the surfaces of glasses and ceramics, thereby reducing the thermal expansion coefficient of this surface region, and creating beneficial state of compressive stress within the near surface region. The purpose of this study was to determine the effects of ion exchange and etching treatments on the strength of some dental porcelains. Two feldspathic dental porcelains(Vitadur-N, G-Cera) were used in this study. A commercial ion exchange paste and etching gel containing 8% hydrofluoric acid were used for surface conditioning. Transverse strength was measured using a universal testing machine and the technique of EPMA(electron probe micro analysis) was used to access the potassium contents. The results were as follows: 1. Improvement in strength was only obtained by treating the surface placed in tension. 2. No changes in the dimensions of the treated specimens were detected when samples were measured with a micrometer. 3. There was significant increase in transverse strength of G-Cera IV group treated with etching and ion exchange, compared with G-Cera II group only treated with ion exchange. 4. From the results of EPMA test, increase in potassium contents was observed on the surface treated with ion exchange paste.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.688-691
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• 1999

Light was of electric lamp was reflected by bulb reflector. In order to improve the efficiency of the electric lamp. it is inevitable that lamp, it is inevitable that improve the reflectance of bulb reflector. Important factors that affect the reflectance of bulb reflector is working pressure, distance between evaporation source to substrate, the situation of surface of glass. etch rate of glass, etc. In this paper. confirmed the effect of etching, working pressure etc. , and its effect for the reflectance of bulb reflector. Especially, concentration of HF in the etching solution and etching time is to be importnace for characteristic of bulb reflector.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.834-837
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• 2004

BST thin films were etched with inductively coupled $CF_4(C1_2+Ar)$ Plasmas. The maximum etch rate of the BST thin films was 53.6 nm/min for a 10 % $CF_4$ to the $Cl_2/Ar$ gas mixture at RF power of 700 W, DC bias of -150 V, and chamber pressure of 2 Pa. Small addition of $CF_4$ to the $Cl_2/Ar$ mixture increased chemical effect. Consequently, the increased chemical effect caused the increase in the etch rate of the BST thin films. To clarify the etching mechanism, the surface reaction of the BST thin films was investigated by X-ray photoelectron spectroscopy.