• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.414-414
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• 2014

박막 태양전지의 광흡수를 증가시키기 위한 방법으로 나노 사이즈의 구조체를 이용하는 방법들이 주목받고 있다. 나노 구조체로 인한 광 산란 효과는 광 흡수층에서 빛의 흡수를 높여 태양전지의 변환효율을 높일 수 있다. 3차원 구조체를 제작하는 기존의 방법들은 대면적 기판에 적용이 어렵고, 비용적 측면 등의 문제점들이 있다. 본 연구에서는 대면적화가 가능한 나노 임프린트 리소그래피 방법을 이용하여 Ag nano rod 패턴을 제작하였다. 임프린트 공정 중 UV 조사시간, 가해지는 하중, 기판온도 등의 변수들과, 건식 이온 식각 시 변수들을 조절하여 최적화된 3차원 rod 패턴을 형성할 수 있었다. 그림 1은 형성된 Ag rod 패턴의 SEM 측정 사진이다. 전극 폭 300 nm, 간격 300 nm로 제조된 rod는 Ag의 두께를 조절함으로써 전기, 광학적 특성을 조절할 수 있었다. 3차원 Ag nano rod를 박막 태양전지의 전, 후면 전극으로 사용하여 태양전지의 특성변화를 분석하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.32.2-32.2
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• 2010

본 연구에서는 고출력, 고휘도를 위해서 개발되고 있는 수직형 LED소자의 광출력향상을 위한 나노 패터닝 공정을 진행하였다. 수직형 LED는 기존 측면형 LED에 비해서 열방출 특성이 우수하고 대면적 칩으로 제작이 가능하기 때문에 높은 광출력이 필요한 조명 분야로의 적용이 가능하다. 하지만 수직형 LED 역시 기존 측면형 LED와 마찬가지로 질화갈륨 및 외부 공기와의 계면에서 전반사가 심하기 때문에 광추출효율이 낮은 문제점이 있으며 이를 해결하는 것이 큰 이슈가 되고 있다. 이를 해결하기 위해서 광결정 패턴을 LED 소자에 형성하여 광추출효율을 향상시키려는 연구가 활발히 진행되고 있으나 아직까지 수직형 LED 웨이퍼 전면적에 균일한 패턴을 형성할 수 있는 기술 개발이 미진한 상황이다. 본 연구에서는 유연 고분자 몰드를 이용한 대면적 나노 임프린팅 및 나노 프린팅 기술을 통해서 2 inch 수직형 LED 웨이퍼 전면적에 균일한 패턴을 전사하는 공정을 진행하였다. 구체적으로는 나노임프린트 및 건식식각 공정을 통해서 수직형 LED의 n형 질화갈륨 층에 높은 가로세로비의 광결정 패턴을 형성하였으며 이를 통해서 약 40% 정도의 광출력이 향상되었다. 또한 고 굴절률의 산화아연 나노 패턴 형성공정을 대면적 LED 기판에 시도하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.400-403
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• 2003

Etching characteristics of (Pb,Sr)$TiO_3$(PST) thin films were investigated using inductively coupled chlorine based plasma system as functions of gas mixing ratio, RF power and DC bias voltage. It was found that increasing of Ar content in gas mixture lead to sufficient increasing of etch rate and selectivity of PST to Pt. The maximum etch rate of PST film is $562\;{\AA}$/min and the selectivity of PST film to Pt is 0.8 at $Cl_2/(Cl_2+Ar)$ of 20 %. It was proposed that sputter etching is dominant etching mechanism while the contribution of chemical reaction is relatively low due to low volatility of etching products.

• 센서학회지
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• 제20권1호
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• pp.58-63
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• 2011

A low loss radio frequency(RF) micro electro mechanical systems(MEMS) switch driven by a low actuation voltage was designed for the development of a new RF MEMS switch. The RF MEMS switch should be encapsulated. The glass cap and fabricated RF MEMS switch were assembled by the Au/Sn eutectic bonding principle for wafer-level packaging. The through-vias on the glass substrate was made by the glass dry etching and Au electroplating process. The packaged RF MEMS switch had an actuation voltage of 12.5 V, an insertion loss below 0.25 dB, a return loss above 16.6 dB, and an isolation value above 41.4 dB at 6 GHz.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권9호
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• pp.616-621
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• 1999

A planar inductively coupled $CH_4/H_2/Ar$plasma was used to investigate dry etch characteristics of GaN as a function of input power, RF bias power, and etch gas composition. Etch rate of GaN increased with input power up to 600 W and was saturated at the higher power. Also, the etch rates increased with increasing RF bias power, composition of $CH_4$ and Ar gas. We achieved the maximum etch rate of $930{\AA}$/min at the input power 400 W, RF bias power 250 W, and operational pressure 10 mTorr. This paper shows that smooth etched surface having roughness less than 1 nm in rms can be obtained by using planar inductively coupled plasma with $CH_4/H_2/Ar$ gas chemistry.

• 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).

• 한국전기전자재료학회논문지
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• 제26권1호
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• pp.1-5
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• 2013

In this paper, we investigated the etching characteristics of the TaN thin films and the surface reaction of TaN thin films after etching process. The etching characteristics of the TaN thin films were carried out using inductively coupled plasma (ICP). The etch rate and the selectivity of TaN to $SiO_2$ and TaN to PR were measured by varying the gas mixing ratio, RF power, DC-bias voltage, and process pressure in CF-based plasma. The surface reaction of TaN thin films were determined by x-ray photoelectron spectroscopy (XPS).

• 대한기계학회논문집A
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• 제31권6호
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• pp.679-685
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• 2007

Superhydrophobic surface, with a water contact angle greater than $150^{\circ}$, has a self-cleaning effect termed 'Lotus effect'. This surface is created by the combination of rough surface and the low surface energy. We proposed square pillar and square shapes to control surface roughness. Microstructure arrays are fabricated by DRIE(Deep Reactive Ion Etching) process and followed by PPFC(Plasma Polymerized Fluorocarbon) deposition. On the experimental result, contact angle at square pillar arrays is well matched with Cassie's model and largest contact angle is $173.37^{\circ}$. But contact angle of square pore shape arrays is lower than Cassie's theoretical contact angle about $5{\sim}10%$. Nevertheless, square pore arrays have more rigidity than square pillar arrays.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.213-216
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• 2001

Etching behaviors of ferroelectric YMn $O_3$ thin films were studied by an inductively coupled plasma (ICP). Etch characteristic on ferroelectric YMn $O_3$ thin film have been investigated in terms of etch rate, selectivity and etch profile. The maximum etch rate of YMn $O_3$ thin film is 300 $\AA$/min at Ar/C $l_2$ of 2/8, RF power of 800W, dc bias voltage of 200V, chamber pressure of 15mTorr and substrate temperature of 3$0^{\circ}C$. Addition of C $F_4$ gas decrease the etch rate of YMn $O_3$ thin film. From the results of XPS analysis, Y $F_{X}$ compunds were found on the surface of YMn $O_3$ thin film which is etched in Ar/C1/C $F_4$ plasma. The etch profile of YMn $O_3$ film is improved by addition of C $F_4$ gas into the Ar/C $l_2$ plasma. These results suggest that fluoride yttrium acts as a sidewall passivants which reduce the sticking coefficient of chlorine on YMn $O_3$.>.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.187-190
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• 2004

In this work, we investigated etching characteristics and mechanism of BST thin films using $Cl_2$/Ar, $CF_4/Cl_2$/Ar and $BCl_3/Cl_2$/Ar gas mixtures using inductively coupled plasma (ICP) system. A chemically assisted physical etch of BST was experimentally confirmed by ICP under various gas mixtures. The etch rate of the BST thin films had a maximum value at 20 $BCl_3$ and 10% $CF_4$ gas concentration, and decreased with further addition of $BCl_3$ or $CF_4$ gas, because $BaCl_x$, $SrCl_x$, $BaF_x$ and $SrF_x$ compounds have higher melting and boiling points. The maximum etch rate of the BST thin films was 57nm/min at the 30% $Cl_2(Cl_2+Ar)$. The characteristics of the plasma were analyzed by using OES and Langmuir probe.