• 정보저장시스템학회논문집
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• 제3권3호
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• pp.118-122
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• 2007

Phase-change wet-etching technology using GeSbTe phase-change films is developed. Selective etching between an amorphous and a crystalline phase can be carried out with an alkaline etchant of NaOH. Etching selectivity is dependent not only on the concentration of the alkaline etchant but also on the film structure. Specifically, metal films for heat control cause marked effects on the etching properties of GeSbTe film. Surviving amorphous pits can be obtained with Al metal layer, however etched amorphous pits are seen with Ag metal layer. An opposite selective etching behavior can be observed between samples with two different metal layers.

• 정보저장시스템학회논문집
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• 제2권3호
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• pp.196-200
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• 2006

We are developing a phase change etching technology using an inorganic photoresist of GeSbTe film which is the recording material of the phase change disc. A selective etching phenomenon between amorphous and crystalline states can be utilized with an alkaline etchant. Phase-change pits could be formed using this technique, in which the etching selectivity is strongly dependent on the concentration of the etchant. The degree of etching was investigated by the transmittance between crystalline and amorphous films after the wet-etching. The pits patterned on the disc could be observed by AFM after wet-etching.

• 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%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.23-26
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• 1997

This work presents the TMAH/IPA anisotropic etching characteristics with addition of Pyrazine. (100) Si etching rate of 0.747 ${\mu}{\textrm}{m}$/min at 8$0^{\circ}C$ was obtained using TMAH 25 wt.% / IPA 17 vol.% / pyrazine 0.1 g. The etching rate of (100) Si is increased about 52% compare to pure TMAH 25 wt.%. But etching rate of (100) Si is decreased with increasing Pyrazine additive. Activation energy of TMAH/IPA/pyrazine is much lower than TMAH and TMAH/IPA solutions. Addition of Pyrazine does not effect on surface flatness and decreases undercutting ratio about 20 %. Therefore, TMAH/IPA/pyrazine is an attractive anisotropic etchant because of alkaline-ion free.

• 한국표면공학회지
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• 제28권1호
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• pp.55-63
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• 1995

Alkaline solutions such as $NH_4$OH, choline and TMAH (($CH_3$)$_4$NOH) have been introduced in semiconductor wet processing of silicon wafers to control ionic and particulate impurities following etching in acidic solutions. These chemicals usually mixed with hydrogen peroxide and/or surfactants to control the etch rate of silicon. The highest etch rate was observed in $NH_4$OH solutions at a pH in alkaline solutions. It indicates that the etch rate depends on the content of $OH^{-}$ as well as cations of alkaline solutions. STM/AFM techniques were used to characterize the effect of alkaline solutions on silicon surface roughness. In SC1 (mixture of $NH_4$OH : $H_2$$O_2$ : $H_2$O) solutions, the reduction of the ammonium hydroxide proportion from 1 to 0.1 decreased the surface roughness ($R_{rms}$) from 6.4 to $0.8\AA$. The addition of $H_2$$O_2$ and surfactants to choline and TMAH reduced the values of $R_{p-v}$ and $R_{rms}$ significantly. $H_2$$_O2$ and surfactants added in alkaline solutions passivate bare silicon surfaces by the oxidation and adsorption, respectively. The passivation of surfaces in alkaline solutions resulted in lower etch rate of silicon thereby provided smoother surfaces.s.ces.s.

• 한국진공학회지
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• 제19권4호
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• pp.314-318
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• 2010

다결정 실리콘 웨이퍼 표면에 대면적 reactive ion etching (RIE) 장비로 표면 텍스쳐를 형성한 뒤 태양전지를 제작하였다. 웨이퍼 표면에 텍스쳐를 형성하는 것은 광학적 손실을 줄이기 위해 일반적으로 사용되는 방법으로 alkaline etching이 사용된다. 그러나 다결정 실리콘 태양전지의 경우 재료의 결정 방향에 따라 식각되는 alkaline etching은 텍스쳐링의 모양을 제어할 수 없어 효과적이지 못하다. 이와 달리 플라즈마 식각방법을 사용하면 표면 텍스쳐의 모양을 효과적으로 제어하여 조금 더 낮은 반사율을 얻을 수 있다. 하지만 텍스쳐 모양 조절로 얻은 낮은 반사율이 항상 높은 변환효율을 얻을 수 있는 것은 아니다. 본 연구에서는 대면적 RIE 공정 조건별로 얻은 태양전지 표면 텍스쳐의 모양에 따라 각각의 반사율과 양자효율 및 변환효율이 미치는 영향을 살펴보았다.

• 한국정보통신학회논문지
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• 제15권11호
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• pp.2439-2443
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• 2011

태양전지를 제작하는데 실리콘기판 표면에서의 광 흡수를 증가시키기 위한 표면조직화를 위해서 염기 용액을 이용한 습식방법을 이용하여 샘플을 제작하였다. 이렇게 준비된 염기성 에칭용액을 이용한 실리콘 웨이퍼의 표면 상태를 관찰하여 광학적 특성과의 연관성을 조사하였다. 표면조직화가 표면 전체적으로 고르게 이루어진 샘플에서 반사도가 낮았으며, 광학적 특성이 좋게 나타났다. 에칭이 과도하게 일어난 샘플에서는 오히려 반사도가 증가하여 광학적 특성이 떨어지는 것을 확인 하였다.

• 전기화학회지
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• 제5권2호
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• pp.43-46
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• 2002

Commercial titanium rod was anodized in three types of electrolytes such as 0.06 mol/L $\beta-glycerophosphate+0.3mol/L$ calcium acetate, 0.06mol/L $\beta-glycerophosphate+0.3mol/L$ sodium acetate and 0.06 mol/L $\beta-glycerophosphate+5mol/L$ calcium phosphate. The titanium oxide layer $(TiO_2)$ was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and electron spectroscopy chemical analysis (ESCA). Numerous micropores were observed on the titanium oxide layer by SEM. The diameter of micropores increased with the increase of electrolytic voltage. The titanium oxide layer was composed of anatase structure. The phosphorous element was detected at 130 eV binding energy, but calcium was not found in the oxide layer because of lower contents. After anodizing the oxide layer was etched in the 30g/L NaOH solution at $80^{\circ}C$ for 1hr. The surroundings of micropores were much more smoothed and rounded than before alkaline etching.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.419-419
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• 2016

High efficiency silicon solar cell requires the textured front surface to reduce reflectance and to improve the light trapping. In case of mono-crystalline silicon solar cell, wet etching with alkaline solution is widespread. However, the alkali texturing methods are ineffective in case of multi-crystalline silicon wafer due to grain boundary of random crystallographic orientation. The acid texturing method is generally used in multi-crystalline silicon wafer to reduce the surface reflectance. However the acid textured solar cell gives low short-circuit current due to high reflectivity while it improves the open-circuit voltage. To reduce the reflectivity of multi-crystalline silicon wafer, double texturing method with combination of acid and reactive ion etching is an attractive technical solution. In this paper, we have studied to optimize RIE experimental condition with change of RF power (100W, 150W, 200W, 250W, 300W). During experiment, the gas ratio of SF6 and O2 was fixed as 30:10.

• 한국전기전자재료학회논문지
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• 제29권8호
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• pp.455-460
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• 2016

A textured front surface is required in high efficiency silicon solar cells to reduce reflectance and to improve light trapping. Wet etching with alkaline solution is usually applied for mono crystalline silicon solar cells. However, alkali texturing method is not appropriate for multi-crystalline silicon wafers due to grain boundary of random crystallographic orientation. Accordingly, acid texturing method is generally used for multi-crystalline silicon wafers to reduce the surface reflectance. To reduce reflectivity of multi-crystalline silicon wafers, double texturing method with combination of acid and reactive ion etching is an attractive technical solution. In this paper, we have studied to optimize RIE condition by different RF power condition (100, 150, 200, 250, 300 W).