• 소성∙가공
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• 제11권7호
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• pp.601-607
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• 2002

Optically transparent materials such as fused silica, quartz and crystal have become important in the filed of optics and optoelectronics. Laser ablation continues to grow as an important technique for micromachining and surface modification of various materials, because many problems caused by direct contact between tools and workpiece can be avoided. Especially, laser ablation with excimer lasers enables fine micromachining of transparent materials such as fused silica, quartz and crystal, etc. In this study, laser-induced wet etching of fused silica in organic solution was conducted. KrF excimer laser was used as a light source and acetone solution of pyrene was used as etchant. Changing the number of laser pulses, micro holes of various depths are fabricated.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1997년도 한국재료학회 춘계학술발표회
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• pp.26-26
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• 1997

• Korean Chemical Engineering Research
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• 제58권3호
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• pp.474-479
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• 2020

유리기판의 박막화를 위한 식각액을 제조하였고, 습식 식각액의 주성분으로 HF를 사용하였다. HF를 기본으로 한 식각액에 HCl, HNO₃, H₂SO₄와 같은 강산과 구연산과 같은 카르복실산 그리고 여러 종류의 아미노산을 첨가물로 각각 사용한 식각액으로 유리의 식각속도와 표면형상의 변화를 측정하였다. 강산의 종류와 상관없이 첨가량이 증가함에 따라 선형적으로 유리의 식각속도가 증가하였으며 유리표면의 슬러지 제거효과도 나타내었다. HCl이 함유된 식각액이 식각속도의 증가율과 슬러지 제거 효과에서 다른 강산보다 효율적인 결과를 보였다. 카르복실산의 첨가는 식각속도에 영향을 크게 주지 않으나 슬러지 제거효과를 보였다. 하지만 아미노산을 첨가한 경우에는 식각속도의 변화와 슬러지 제거 효과가 크지 않았다.

• 한국결정성장학회지
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• 제32권1호
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• pp.40-44
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• 2022

35 % 농도의 염산 용액을 이용하여 α-Ga₂O₃ epitaxy 박막의 습식 식각을 수행하였다. 35 % 염산 용액의 온도가 증가함에 따라 α-Ga₂O₃ epitaxy 박막의 식각 속도가 증가하였고, 본 연구에서 시도한 가장 높은 온도인 75℃에서 119.6 nm/min의 식각 속도를 나타내었다. 식각 반응의 활성화 에너지는 0.776 eV로 계산되었고, HCl 용액에서의 습식 식각은 reaction-limited 반응 기구에 의해 지배됨을 확인하였다. 각 온도에서 식각된 표면들의 AFM 분석결과 식각 용액의 온도가 증가함에 따라 식각된 표면의 표면조도가 증가함을 알 수 있었다.

• 구강회복응용과학지
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• 제37권1호
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• pp.23-30
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• 2021

목적: 본연구의 목적은 다양한 산용액을 이용하여 지르코니아의 표면을 처리하여 표면의 양상과 골유착에 미치는 영향을 알아보는 것이다. 연구 재료 및 방법: 준비된 지르코니아 디스크에 다양한 산용액 및 광촉매 산부식을 이용하여 표면을 처리하였다. 각 시편을 SEM으로 관찰하고, 골유착을 관찰하기 위해 MC3T3E-1 세포를 이용하여 형광염색과 역전사 중합효소 연쇄반응을 통해 평가하였다. 결과: 처리한 방법에 따라 다양한 거칠기를 보였다. 불산처리군은 표면의 거칠기가 증가하였으나 약한 네트워크 구조를 가지고 있었다. 골유착능에서는 광촉매 산부식을 시행한 군에서 더 좋은 결과를 보였다(P < 0.05). 결론: 지르코니아를 광촉매 산부식방법으로 처리할 경우 다른 산처리방법에 비해 골유착능을 높이는데 효과적일 것으로 사료된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.241-241
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• 2008

Macrofore formation in silicon and other semiconductors using electrochemical etching processes has been, in the last years, a subject of great attention of both theory and practice. Its first reason of concern is new areas of macropore silicone applications arising from microelectromechanical systems processing (MEMS), membrane techniques, solar cells, sensors, photonic crystals, and new technologies like a silicon-on-nothing (SON) technology. Its formation mechanism with a rich variety of controllable microstructures and their many potential applications have been studied extensively recently. Porous silicon is formed by anodic etching of crystalline silicon in hydrofluoric acid. During the etching process holes are required to enable the dissolution of the silicon anode. For p-type silicon, holes are the majority charge carriers, therefore porous silicon can be formed under the action of a positive bias on the silicon anode. For n-type silicon, holes to dissolve silicon is supplied by illuminating n-type silicon with above-band-gap light which allows sufficient generation of holes. To make a desired three-dimensional nano- or micro-structures, pre-structuring the masked surface in KOH solution to form a periodic array of etch pits before electrochemical etching. Due to enhanced electric field, the holes are efficiently collected at the pore tips for etching. The depletion of holes in the space charge region prevents silicon dissolution at the sidewalls, enabling anisotropic etching for the trenches. This is correct theoretical explanation for n-type Si etching. However, there are a few experimental repors in p-type silicon, while a number of theoretical models have been worked out to explain experimental dependence observed. To perform ordered macrofore formaion for p-type silicon, various kinds of mask patterns to make initial KOH etch pits were used. In order to understand the roles played by the kinds of etching solution in the formation of pillar arrays, we have undertaken a systematic study of the solvent effects in mixtures of HF, N-dimethylformamide (DMF), iso-propanol, and mixtures of HF with water on the macrofore structure formation on monocrystalline p-type silicon with a resistivity varying between 10 ~ 0.01 $\Omega$ cm. The etching solution including the iso-propanol produced a best three dimensional pillar structures. The experimental results are discussed on the base of Lehmann's comprehensive model based on SCR width.

• 한국세라믹학회지
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• 제46권6호
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• pp.685-688
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• 2009

Surface Texturing is very important process for high cell efficiency in crystalline silicon solar cell. Anisotropic texturing with an alkali etchant was known not to be able to produce uniform surface morphology in multi-crystalline silicon (mc-Si), because of its different etching rate with random crystal orientation. In order to reduce surface reflectance of mc-Si wafer, the general etching tendency was studied with HF/HN$O_3$/De-ionized Water acidic solution. And the surface structures of textured mc-Si in various HF/HN$O_3$ ratios were compared. The surface morphology and reflectance of textured silicon wafers were measured by FE-SEM and UVvisible spectrophotometer, respectively. We obtained average reflectance of $16{\sim}19$% for wavelength between 400 nm and 900 nm depending on different etching conditions.

• 한국표면공학회지
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• 제40권3호
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• pp.138-143
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• 2007

The effects of texturing and anti-reflection coating on the reflection properties of multi-crystalline silicon solar cell have been investigated. The chemical solutions of alkaline and acidic etching solutions were used for texturing at the surface of multi-crystalline Si wafer. Experiments were performed with various temperature and time conditions in order to determine the optimized etching condition. Alkaline etching solution was found inadequate to the texturing of multi-crystalline Si due to its high reflectance of about 25%. The reflectance of Si wafer texturing with acidic etching solution showed a very low reflectance about 10%, which was attributed to the formation of homogeneous. Also, deposition of ITO anti-reflection coating reduced the reflectance of multi-crystalline si etched with acidic solution($HF+HNO_3$) to 2.6%.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권7호
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• pp.354-358
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• 2006

In this paper, we investigated the selective etching rate of amorphous As-Ge-Se-S thin film due to the photoexpansion effect and fabricated the 2-dimensional embossing type diffraction grating hologram. We measured the thickness change with the etching time among NaOH solution after forming 1-dimension diffraction grating. As a results, we found that the selective etching rate were $2.5\AA/s,\;3.3\AA/s,\;3.9\AA/s$ where NaOH solution concentration were 0.26N, 0.33N, 0.36N, respectively. Also after the formation of 2-dimensional diffraction grating by the $90^{\circ}$ degree of circulation on the formed 1-dimensional diffraction grating, we etched selectively during 60sec, among 0.26N NaOH solution and obtained 2-dimensional embossing diffraction grating. As the results of AFM (Atomic Force Microscopy), we confirmed the formation of distinct embossing type 2-dimensional diffraction grating hologram, successfully.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권6호
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• pp.367-374
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• 2000

This paper presents a method to fabricate freestanding structures by (100) silicon anisotropic etching and nickel electroless plating. The electroless plating process is simpler than the electroplating, and provides good coating uniformity and improved mechanical properties. Furthermore, the (100) silicon anisotropic etching in KOH solution with being aligned to <100> direction provides vertical (100) sidewalls on etched (100) surface. In this paper, the effects of the nickel electroless plating condition on the properties of electroless plated metal structures are investigated to apply fabrication of micro structures and then various micro structures are fabricated by nickel electroless plating. And then, the structures are released by silicon anisotropic etching in KOH solution with a large gap between the structure and the substrate. The fabricated cantilever structures are $210\mum$. wide, $5\mum$. thick and $15\mum$. over the silicon substrate, and the comb structure has the comb electrodes which are $4\mum$. wide and $4.3\mum$. thick separated by$1\mum$. It is released by silicon anisotropic etching in KOH solution. The gap between the structure and the substrate is $2.5\mum$.