• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1054-1057
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• 2004

The nitrogenated diamond-like carbon (NDLC) exhibits high electrical resistivity and thermal conductivity that are similar to the properties shown by diamond-like carbon (DLC) films. These diamond-like transparent properties in NDLC come in a material consisting of $sp^2$-bonded carbon versus the $sp^3$-carbon of DLC. The diamond-like properties and nondiamond-like bonding make NDLC an attractive candidate for applications. Liquid crystal (LC) alignment capabilities with ion beam exposure on NDLC thin films and electro-optical (EO) performances of the ion-beam-aligned twisted nematic liquid crystal display (TN-LCD) with oblique ion beam exposure on the NDLC thin film surface were studied. An excellent uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the NDLC thin films was observed. In addition, it can be achieved that the good EO properties of the ion-beam-aligned TN-LCD. Finally, we will present the residual DC property of the ion-beam-aligned TN-LCD on the NDLC thin film surface.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.166-166
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• 2010

Recently, TFTs based on amorphous oxide semiconductors (AOSs) such as ZnO, InZnO, ZnSnO, GaZnO, TiOx, InGaZnO(IGZO), SnGaZnO, etc. have been attracting a grate deal of attention as potential alternatives to existing TFT technology to meet emerging technological demands where Si-based or organic electronics cannot provide a solution. Since, in 2003, Masuda et al. and Nomura et al. have reported on transparent TFTs using ZnO and IGZO as active layers, respectively, much efforts have been devoted to develop oxide TFTs using aforementioned amorphous oxide semiconductors as their active layers. In this thesis, I report on the performance of thin-film transistors using amorphous indium gallium zinc oxides for an active channel layer at room temperature. $SiO_2$ was employed as the gate dielectric oxide. The amorphous indium gallium zinc oxides were deposited by RF magnetron sputtering. The carrier concentration of amorphous indium gallium zinc oxide was controlled by oxygen pressure in the sputtering ambient. Devices are realized that display a threshold voltage of 1.5V and an on/off ration of > $10^9$ operated as an n-type enhancement mode with saturation mobility with $9.06\;cm^2/V{\cdot}s$. The devices show optical transmittance above 80% in the visible range. In conclusion, the fabrication and characterization of thin-film transistors using amorphous indium gallium zinc oxides for an active channel layer were reported. The operation of the devices was an n-type enhancement mode with good saturation characteristics.

• 대한금속재료학회지
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• 제47권1호
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• pp.44-49
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• 2009

본 연구에서는 2인치 ITO의 타깃으로 ITO박막을 성장시킨 후 RTA 처리로 인한 전기적, 광학적 특성의 변화를 조사하였으며, RTA 처리된 ITO 박막을 이용하여 플라즈마 응용 사인보드를 제작 및 구동하였다. RTA공정으로 열처리한 ITO는 투과도는 증가하며, 비저항은 감소함을 관찰하였으며, 투과도의 증가는 RTA로 인한 결정성의 증가로 인한 결과이고, 비저항의 감소는 결정성의 증가와 더불어 치환형 주석의 원자수가 증가하였다고 사료된다. ITO를 이용하여 사인보드 제작시 방전cell의 압력은 3-5 Torr가 적당함을 알 수 있었으며, 전극 간격을 조절하여 120 V 정도의 낮은 플라즈마 개시 전압을 갖는 플라즈마 응용 사인보드를 성공적으로 제작 할 수 있었다.

• 한국중재학회지:중재연구
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• 제32권2호
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• pp.135-157
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• 2022

Religion has a very close relationship with our everyday lives. In particular, religion maintains an absolute and ultimate value system and is deeply associated with all sectors of society such as politics, economy, thought, arts, culture, and science. The original meaning of religion in Buddhism means the teachings that become fundamentals. There are numerous religions around the world, and each religion has its own object of faith, different system, and unique rites and lifestyles. Therefore, evaluating or denouncing other regions based on the doctrines or conventions of a specific religion can lead to conflicts and disputes. The Buddhist Vinaya Pitaka related to alternative dispute resolution (ADR) is a method regarding the operation of a community. Vinaya Pitaka contains Buddha's teachings about individual and organizational ethics and on community life and activities. It is the Buddhist dispute resolution (BDR) of the Vinayata Pitaka that contains knowledge on howto remedy disputes among the four types of disputes that can occur. Vinaya Pitaka contains the principles and systems of BDR, and it is sufficient background for succeeding in the development of harmony today. The messages of laws, ethics, and Buddhist teachings are clear in these characteristics. The systems, progress, and procedures for various rites, events, and disputes as well as for everyday life, etc. display a rational operating system through karma. In particular, when disputes occur, the cause of the dispute is resolved as much as possible through transparent fairness and being unanimous using the seven remedies for disputes. Buddhist priests pursue private autonomy of ADR through karma, repentance, acceptance, etc. to maintain and continue the integrated functions of Buddhist priest harmony.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.100-101
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• 2012

The plasma damage free and room temperature processedthin film deposition technology is essential for realization of various next generation organic microelectronic devices such as flexible AMOLED display, flexible OLED lighting, and organic photovoltaic cells because characteristics of fragile organic materials in the plasma process and low glass transition temperatures (Tg) of polymer substrate. In case of directly deposition of metal oxide thin films (including transparent conductive oxide (TCO) and amorphous oxide semiconductor (AOS)) on the organic layers, plasma damages against to the organic materials is fatal. This damage is believed to be originated mainly from high energy energetic particles during the sputtering process such as negative oxygen ions, reflected neutrals by reflection of plasma background gas at the target surface, sputtered atoms, bulk plasma ions, and secondary electrons. To solve this problem, we developed the NBAS (Neutral Beam Assisted Sputtering) process as a plasma damage free and room temperature processed sputtering technology. As a result, electro-optical properties of NBAS processed ITO thin film showed resistivity of $4.0{\times}10^{-4}{\Omega}{\cdot}m$ and high transmittance (>90% at 550 nm) with nano- crystalline structure at room temperature process. Furthermore, in the experiment result of directly deposition of TCO top anode on the inverted structure OLED cell, it is verified that NBAS TCO deposition process does not damages to the underlying organic layers. In case of deposition of transparent conductive oxide (TCO) thin film on the plastic polymer substrate, the room temperature processed sputtering coating of high quality TCO thin film is required. During the sputtering process with higher density plasma, the energetic particles contribute self supplying of activation & crystallization energy without any additional heating and post-annealing and forminga high quality TCO thin film. However, negative oxygen ions which generated from sputteringtarget surface by electron attachment are accelerated to high energy by induced cathode self-bias. Thus the high energy negative oxygen ions can lead to critical physical bombardment damages to forming oxide thin film and this effect does not recover in room temperature process without post thermal annealing. To salve the inherent limitation of plasma sputtering, we have been developed the Magnetic Field Shielded Sputtering (MFSS) process as the high quality oxide thin film deposition process at room temperature. The MFSS process is effectively eliminate or suppress the negative oxygen ions bombardment damage by the plasma limiter which composed permanent magnet array. As a result, electro-optical properties of MFSS processed ITO thin film (resistivity $3.9{\times}10^{-4}{\Omega}{\cdot}cm$, transmittance 95% at 550 nm) have approachedthose of a high temperature DC magnetron sputtering (DMS) ITO thin film were. Also, AOS (a-IGZO) TFTs fabricated by MFSS process without higher temperature post annealing showed very comparable electrical performance with those by DMS process with $400^{\circ}C$ post annealing. They are important to note that the bombardment of a negative oxygen ion which is accelerated by dc self-bias during rf sputtering could degrade the electrical performance of ITO electrodes and a-IGZO TFTs. Finally, we found that reduction of damage from the high energy negative oxygen ions bombardment drives improvement of crystalline structure in the ITO thin film and suppression of the sub-gab states in a-IGZO semiconductor thin film. For realization of organic flexible electronic devices based on plastic substrates, gas barrier coatings are required to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency flexible AMOLEDs needs an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}gm^{-2}day^{-1}$. The key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required (under ${\sim}10^{-6}gm^{-2}day^{-1}$) is the suppression of nano-sized defect sites and gas diffusion pathways among the grain boundaries. For formation of high quality single inorganic gas barrier layer, we developed high density nano-structured Al2O3 single gas barrier layer usinga NBAS process. The NBAS process can continuously change crystalline structures from an amorphous phase to a nano- crystalline phase with various grain sizes in a single inorganic thin film. As a result, the water vapor transmission rates (WVTR) of the NBAS processed $Al_2O_3$ gas barrier film have improved order of magnitude compared with that of conventional $Al_2O_3$ layers made by the RF magnetron sputteringprocess under the same sputtering conditions; the WVTR of the NBAS processed $Al_2O_3$ gas barrier film was about $5{\times}10^{-6}g/m^2/day$ by just single layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.5-5
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• 2009

Thin-film-transistors (TFTs) that can be prepared at low temperatures have attracted much attention because of the great potential for transparent and flexible electronics. One of the mainstreams in this field is the use of organic semiconductors such as pentacene. But device performance of the organic TFTs is still limited due to low field-effect mobility and rapid degradation after exposing to air. Alternative approach is the use of amorphous oxide semiconductors as a channel. Amorphous oxide semiconductors (AOSs) based TFTs showed the fast technological development, because AOS films can be fabricated at room temperature and exhibit the possibility in application like flexible display, electronic paper, and larges solar cells. Among the various AOSs, a-IGZO has lots of advantages because it has high channel mobility, uniform surface roughness and good transparency. [1] The high mobility is attributed to the overlap of spherical s-orbital of the heavy post-transition metal cations. This study demonstrated the effect of the variation in channel thickness from 30nm to 200nm on the TFT device performance. When the thickness was increased, turn-on voltage and subthreshold swing was decreased. The a-IGZO channels and source/drain metals were deposited with shadow mask. The a-IGZO channel layer was deposited on $SiO_2$/p-Si substrates by RF magnetron sputtering, where RF power is 150W. And working pressure is 3m Torr, at $O_2/Ar$ (2/28 sccm) atmosphere. The electrodes were formed with electron-beam evaporated Ti (30 nm) and Au (70 nm) bilayer. Finally, Al (150nm) as a gate metal was thermal-evaporated. TFT devices were heat-treated in a furnace at 250 $^{\circ}C$ and nitrogen atmosphere for 1hour. The electrical properties of the TFTs were measured using a probe-station. The TFT with channel thickness of 150nm exhibits a good subthreshold swing (SS) of 0.72 V/decade and on-off ratio of $1{\times}10^8$. The field effect mobility and threshold voltage were evaluated as 7.2 and 8 V, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.137-137
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• 2009

Thin-film transistors (TFTs) that can be prepared at low temperatures have attracted much attention due to the great potential for flexible electronics. One of the mainstreams in this field is the use of organic semiconductors such as pentacene. But device performance of the organic TFTs is still limited by low field effect mobility or rapidly degraded after exposing to air in many cases. Another approach is amorphous oxide semiconductors. Amorphous oxide semiconductors (AOSs) have exactly attracted considerable attention because AOSs were fabricated at room temperature and used lots of application such as flexible display, electronic paper, large solar cells. Among the various AOSs, a-IGZO was considerable material because it has high mobility and uniform surface and good transparent. The high mobility is attributed to the result of the overlap of spherical s-orbital of the heavy pest-transition metal cations. This study is demonstrated the effect of thickness channel layer from 30nm to 200nm. when the thickness was increased, turn on voltage and subthreshold swing were decreased. a-IGZO TFTs have used a shadow mask to deposit channel and source/drain(S/D). a-IGZO were deposited on SiO2 wafer by rf magnetron sputtering. using power is 150W, working pressure is 3m Torr, and an O2/Ar(2/28 SCCM) atmosphere at room temperature. The electrodes were formed with Electron-beam evaporated Ti(30nm) and Au(70nm) structure. Finally, Al(150nm) as a gate metal was evaporated. TFT devices were heat treated in a furnace at $250^{\circ}C$ in nitrogen atmosphere for an hour. The electrical properties of the TFTs were measured using a probe-station to measure I-V characteristic. TFT whose thickness was 150nm exhibits a good subthreshold swing(S) of 0.72 V/decade and high on-off ratio of 1E+08. Field effect mobility, saturation effect mobility, and threshold voltage were evaluated 7.2, 5.8, 8V respectively.

• 대한기계학회논문집B
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• 제35권1호
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• pp.17-22
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• 2011

실험을 통해 구현한 ZnO 기반의 투명 박막트랜지스터의 기계적 특성을 분석하고 안정성에 대한 확보방안을 제시하기 위해 FEM (Finite Element Method)을 이용하여 소자를 구성하는 브릿지 와 패드 부분에 대한 구조해석을 실시하였다. 소자의 유연성 확보를 위해 설계된 브릿지 부분의 웨이브 패턴을 구현한 결과 실험 값 대비 최대 진폭의 크기가 오차 0.5%로 실험값과 유사한 신뢰성 있는 결과 값을 얻어낼 수 있었다. 이러한 결과를 바탕으로 브릿지와 패드 사이에 나타나는 압축 응력을 확인하였으며, 압축 응력 값을 패드에 적용하여 그 변형 정도를 분석하였다. 기계적으로 안정성을 갖는 소자를 설계하기 위해 $SiO_2$ 절연층위의 ITO 전극과 ZnO 활성 층의 위치 및 크기를 예측 하였으며, SU-8 코팅 두께를 조절함으로써 중성 역학 층 (Neutral Mechanical Plane)의 위치와 구조적 타당성에 대하여 분석하였다.

• 한국진공학회지
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• 제20권5호
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• pp.356-360
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• 2011

유리 기판 위에 RF와 DC 마그네트론 스퍼터링 방법으로 100 nm 두께의 $In_2O_3$ 단층 박막과 $In_2O_3$ 100 nm/Cu 3 nm의 두께를 갖는 적층박막을 증착하고, 구리 기저 층 증착에 따른 상부 $In_2O_3$ 박막의 광학적, 전기적 특성의 변화를 연구하였다. 상온에서 증착 된 $In_2O_3$ 박막의 가시광 투과도와 면 저항은 79%와 2,300 ${\Omega}/{\square}$이었다. 구리 기저 층의 광 흡수에 의하여, $In_2O_3$/Cu 적층박막의 가시광 투과도는 71%로 감소하였으나, 면 저항은 110 ${\Omega}/{\square}$로 측정되어 상대적으로 우수한 전기적 특성을 구할 수 있었다. 본 연구에서 Figure of Merit 분석을 통하여 구리 기저 층이 상부 $In_2O_3$ 투명전극의 전기적, 광학적 특성을 개선 할 수 있음을 확인하였다.

• 한국광학회지
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• 제28권6호
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• pp.356-360
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• 2017

ITO는 높은 전기 전도도와 가시광선, 근적외선 영역에서 투명성을 가진다. LCD, OLED 등을 포함한 광학에 적용되는 부품들의 제조에 투명전극으로 ITO가 사용되고 있다. 가시광선 영역에서의 투명성과 높은 전도도 때문에 다양한 전기, 디스플레이 센서의 전극으로 이용되었다. 한 가지 사안은 기판의 특성에 충격없이 ITO, 금속 필름같은 특정한 영역의 층을 제거하는 부분이다. 레이저를 사용한 유리 위의 ITO 제거는 기존 방법에 비해 친환경적이다. 본 연구는 펨토초 레이저와 나노초 레이저를 사용하여 ITO를 제거하는 비교분석이다.