• Journal of Magnetics
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• 제18권2호
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• pp.163-167
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• 2013

We fabricated prototype cantilevers for mechanically detected high-frequency ESR measurement. Cantilevers are fabricated from silicon-on-insulator (SOI) wafers using standard MEMS techniques such as lithography, wet etching, and plasma etching. Using commercial SOI wafers, fabrication cost and the number of processes can be substantially reduced. In this study, three types of cantilevers, designed for capacitive and optical detection, are shown. Capacitive type with lateral dimensions of $3.5{\times}1.6mm^2$ is aimed for low spin concentration sample. On the other hand, optical detection type with lateral dimensions of $50{\times}200{\mu}m^2$ is developed for high-sensitive detection of tiny samples such as newly synthesized microcrystals.

• 한국전기전자재료학회논문지
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• 제14권9호
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• pp.751-756
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• 2001

Carbon nanotubes(CNTs) was successfully grown on Ni coated silicon wafer substrate by PECVD technique(Plasma Enhanced Chemical Vapor Deposition). As a catalyst, Ni thin film of thickness ranging from 15∼30nm was prepared by electron beam evaporator system. In order to find the find the optimum growth condition, initially two different types of gas mixtures such as C$_2$H$_2$-NH$_3$ and C$_2$H$_2$-NH$_3$-Ar were systematically investigated by adjusting the gas mixing ratio in temperature of 600$^{\circ}C$ under 0.4 torr. The diameter of the grown CNTs was 40∼200nm. The diameter of the CNTs increases with increasing the Ni particles size. TEM images clearly demonstrated synthesized nanotubes to be multiwalled.

• Transactions on Electrical and Electronic Materials
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• 제7권4호
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• pp.173-179
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• 2006

Due to the limitations of the channel length, the lateral spread for two-dimensional impurity distributions is critical for the analysis of devices including the integrated complementary metal oxide semiconductor (CMOS) circuits and high frequency semiconductor devices. The developed codes were then compared with the two-dimensional implanted profiles measured by transmission electron microscope (TEM) as well as simulated by a commercial TSUPREM4 for verification purposes. The measured two-dimensional TEM data obtained by chemical etching-method was consistent with the results of the developed analytical model, and it seemed to be more accurate than the results attained by a commercial TSUPREM4. The developed codes can be applied on a wider energy range $(1KeV{\sim}30MeV)$ than a commercial TSUPREM4 of which the maximum energy range cannot exceed 1MeV for the limited doping elements. Moreover, it is not only limited to diffusion process but also can be applied to implantation due to the sloped and nano scale structure of the mask.

• Journal of information and communication convergence engineering
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• 제10권3호
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• pp.295-299
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• 2012

Defect generation during organic bottom anti-reflective coating (BARC) in the photo lithography process is closely related to humidity control in the BARC coating unit. Defects are related to the water component due to the humidity and act as a blocking material for the etching process, resulting in an extreme pattern bridging in the subsequent BARC etching process of the poly etch step. In this paper, the lower limit for the humidity that should be stringently controlled for to prevent defect generation during BARC coating is proposed. Various images of defects are inspected using various inspection tools utilizing optical and electron beams. The mechanism for defect generation only in the specific BARC coating step is analyzed and explained. The BARC defect-induced gate pattern bridging mechanism in the lithography process is also well explained in this paper.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.509-512
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• 2001

Aluminum nitride(AIN) thin films were deposited on silicon substrates using RF magnetron sputtering at various deposition conditions and investigated the characteristics. It was used XRD, AES, SEM, and HP-4145B semiconductor parameter analyzer to analysis deposited AIN thin films. The deposition conditions for the good c-axis orientation were 100 W of RF power, 200$^{\circ}C$ of substrate temperature and 15 mTorr of working Pressure. The leakage current density was less then 1.3${\times}$10$\^$-7/ A/$\textrm{cm}^2$. And it was also investigated the etching properties of deposited AIN thin films for application.

• Transactions on Electrical and Electronic Materials
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• 제17권4호
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• pp.204-207
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• 2016

Experimental study of UV-irradiated O₂/H₂ gas phase cleaning for PMMA (Polymethylmethacrylate) removal is carried out in a load-locked reactor equipped with a UV lamp and PBN heater. UV enhanced O₂/H₂ gas phase cleaning removes polymethylmethacrylate (PMMA) better at lower process pressure with higher content of H₂. O₂ gas compete for UV (184.9 nm) absorption with PMMA producing O₃, O(¹D) and lower dissociation of PMMA. In our experimental conditions, etching reaction of PMMA at the substrate temperature between 75℃ and 125℃ had activation energy of about 5.86 kcal/mol indicating etching was controlled by surface reaction. Above the 180℃, PMMA removal was governed by a supply of reaction gas rather than by substrate temperature.

• 한국진공학회지
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• 제12권4호
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• pp.288-292
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• 2003

Air hole 구조를 갖는 2차원 고분자 광결정 도파로를 나노 임프린트 방법으로 제작하기 위하여, e-beam lithography와 ICP etching 공정을 이용하여 기둥 구조를 갖는 실리콘 나노 마스터를 제작하였다. Air hole 구조를 갖는 광결정 구조를 얻기 위해, 실리콘 마스터 기둥의 형태를 4각형, 6각형, 12각형 및 원으로 설계하였다. 제작된 기둥의 직경과 구조를 CD-SEM과 SPM-AFM을 이용하여 측정하였으며, dose가 432 $\mu$C/$\textrm{cm}^2$일 때 최적의 dose임을 확인하였다.

• 센서학회지
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• 제30권5호
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• pp.273-278
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• 2021

Here, we studied the change in the mechanical stiffness of a diaphragm according to the corrugation pattern. The diaphragm consists of a silicon oxide and nitride double layer; a corrugation pattern was formed by dry etching, and the diaphragm was released by wet etching. The fabrication of the thin film was verified using focused ion beam and scanning electron microscopy images. The mechanical stiffness of the diaphragm was obtained by measuring the surface vibration using a laser Doppler vibrometer while applying external sound pressure. Flat squares, diaphragms with square corrugations, and circular corrugation patterns were measured and compared. The stiffness of the diaphragm with a corrugation structure was found to be smaller than that without a corrugation structure; in particular, circular corrugation showed a better effect because of the high symmetry. Furthermore, the effect of corrugation was theoretically predicted. The proposed corrugated diaphragm showed comparable flexibility with the state-of-the-art MEMS microphone diaphragm.

• 한국결정성장학회지
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• 제20권1호
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• pp.7-11
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• 2010

단결정 실리콘 태양전지의 광학적 손실을 감소시키는 표면 텍스쳐링은 최종 셀의 효율을 향상시키기 위하여 매우 중요하다. 본 연구에서는 2-step texturing의 공정으로 기존의 텍스쳐링에서 이루어진 피라미드에 수 많은 sub-micrometer 사이즈의 구조를 형성시켰다. $AgNO_3$ 용액으로 웨이퍼 표면에 Ag코팅을 한 후, 그 웨이퍼를 다시 HF/$H_2O_2$ 용액으로 수십초 동안 식각을 거치게 된다. 결과적으로, 피라미드 위에 생성된 수 nm사이즈의 구조물들은 $AgNO_3$의 농도 및 식각 시간의 변화에 의해 그 크기와 굵기가 변화하는 것을 알 수 있었다. 웨이퍼의 표면이 2-step texturing에 의해 식각이 이루어지면 연잎의 거친 표면과 비슷해지고, 그 결과 평균 10% 이상의 반사율을 보이던 기존 웨이퍼에서 3% 이하의 낮은 반사율을 얻을 수 있었다. 이는 일반적인 텍스쳐링과 anti-reflection coating을 거친 웨이퍼의 반사율보다 낮은 결과이다.

• 전기화학회지
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• 제4권1호
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• pp.10-13
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• 2001

광전기화학적 양극 산화법으로 다공질 실리콘 (porous silicon, PS)을 제조할 때 전해질에 음이온성 계면활성제의 한 종류인 Pentadecafluorooctanoic acid (PDFO)를 첨가하여 제조한 PS의 광발광(photoluminescence, PL)의 변화를 조사하였다. 사용한 웨이퍼는 비저항이 $0.4\~0.8{\Omega}{\cdot}cm$인 n-형 단결정 실리콘 (100)이었으며, 일정전위 4V를 600초 동안 걸어주어 다공성 실리콘을 제조하였다. 이 때 나타난 PL의 변화는 첨가한 계면활성제의 농도가 1mM에서 50mM로 증가함에 따라서 PL의 중심파장이 600nm에서 550nm로 단파장 이동함을 보여주었으며, PL의 세기는 감소함을 보여주었다. FT-IR을 사용하여 에칭된 다공성 실리콘 위에 PDFO가 존재함을 알 수 있었고 Goniometer를 사용한 물방울 각도 측정을 통해서 생성된 표면이 소수성임을 알 수 있었다. 이로부터 계면활성제의 소수성 부분인 포화탄화불소 사슬 부분이 표면에 전체적으로 누워있다고 유추하였다.