• Korean Journal of Materials Research
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• v.19 no.7
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• pp.376-381
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• 2009

Indium Tin Oxide (ITO) thin films on Polyethylene Terephtalate (PET) substrate were prepared by Roll-to-Roll sputter system with targets of 5 wt% and 10 wt% $SnO_2$ at room temperature. The influence of the chromaticity (b*) and transmittance properties of the ITO Films were investigated. The ITO thin films were deposited as a function of the DC power, rolling speed, and Ar/$O_2$ gas flow ratio, and then characterized by spectrophotometer. Their crystallinity and surface resistance were also analyzed by X-ray diffractometer and 4-point probe. As a result, the chromaticity (b*) and transmittance of the ITO films were broadly dependent on the thickness, which was controlled by the rolling speed. When the ITO films were prepared with the DC power of 300 W and the Ar/$O_2$ gas flow ratio of 30/1 sccm using 10 wt% $SnO_2$ target as a function of the rolling speeds 0.01 through 0.10 m/min, its chromaticity (b*) and transmittance were about -4.01 to 11.28 and 75.76 to 86.60%, respectively. In addition, when the ITO films were deposited with the DC power of 400W and the Ar/$O_2$ gas flow ratio of 30/2 sccm used in 5 wt% $SnO_2$ target, its chromaticity (b*) and transmittance were about -2.98 to 14.22 and 74.29 to 88.52%, respectively.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.41
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• pp.221-229
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• 1997

This study concerns with the comparing and evaluation for Signal - Noise Ratio of the quantitative signal factors in the measurement devices for developing efficiency for product system. On the basis of this conditions and purpose, this study presents a general procedure for deriving the Signal - Noise Ratio, confidence intervals and significiant testing for the measurement devices.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.4
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• pp.329-337
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• 1993

Improvement of orthognathic surgical techniques make it possible to design esthetic surgical correction for total esthetic face. In order to find the esthetic line which guide esthetic surgical correction in patients of orthognathic surgery, cephalometric soft tissue analysis of esthetic faces were performed. In esthetic Korean young adults, 25 males and 25 females who were within 1 S.D. of E-line, ANB, P/A facial height ratio, were analyzed in natural position keeping their face eye level. 1. Sn position is constant in males and females. The Sn-N'-N' Vertical plane angle is $5.3^{\circ}$ in both sexes. Sn is positioned in front of 5 mm in female 7 mm in male from the N' vertical plane. 2. The Sn-Ls line make constant angle to horizontal plane with $72.5^{\circ}$ in both sexes, which is called "upper esthetic line". The Ls-Pg' line makes constant angle to $72.4^{\circ}$ (range $72.2^{\circ}$ in female to $72.6^{\circ}$ in male), which is called "lower esthetic line". 3. When inter-esthetic line angle (the Sn-Ls line to Ls-Pg' line) has $144.9^{\circ}$, lower third face has esthetic upper and lower lip. 4. In treatment planning, Sn is first corrected in proper position, and then upper and lower esthetic line are established with the angle of 144.9. The maxilla is moved to tangent Ls to the upper esthetic line, and mandible is moved to tangent Li and Pg' to the lower esthetic line, according to the "y"-shaped esthetic lines, then lower third face showes esthetics.

• Korean Journal of Materials Research
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• v.20 no.9
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• pp.494-499
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• 2010

Tin oxide thin films were prepared on borosilicate glass by rf reactive sputtering at different deposition powers, process pressures and substrate temperatures. The ratio of oxygen/argon gas flow was fixed as 10 sccm / 60 sccm in this study. The structural, electrical and optical properties were examined by the design of experiment to evaluate the optimized processing conditions. The Taguchi method was used in this study. The films were characterized by X-ray diffraction, UV-Vis spectrometer, Hall effect measurements and atomic force microscope. Tin oxide thin films exhibited three types of crystal structures, namely, amorphous, SnO and $SnO_2$. In the case of amorphous thin films the optical band gap was widely spread from 2.30 to 3.36 eV and showed n-type conductivity. While the SnO thin films had an optical band gap of 2.24-2.49 eV and revealed p-type conductivity, the $SnO_2$ thin films showed an optical band gap of 3.33-3.63 eV and n-type conductivity. Among the three process parameters, the plasma power had the most impact on changing the structural, electrical and optical properties of the tin oxide thin films. It was also found that the grain size of the tin oxide thin films was dependent on the substrate temperature. However, the substrate temperature has very little effect on electrical and optical properties.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.213-213
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• 1999

현재 LCD용 기판재료는 ITO/glass를 전극으로 사용하고 있다. 그러나 유리기판은 무겁고 깨지기 쉽기 때문에 사용상 곤란한 점이 많다. 최근 flexible하고 가공성 및 생산성이 우수한 플라스틱한 ITO를 성막하여 EL용, Touch panel, plastic LCD용 사용하려는 시도로, roll-to-roll 연속 스퍼터링에 의한 ITO성막공정에 대한 연구가 최근 활발하게 이루어지고 있다. 폴리머는 유리에 비해 Tg 온도가 낮고, 기판으로부터의 수분 및 여러 종류의 가스방출이 심하기 때문에 유리와는 달리 ITO막의 제조에 있어 큰 차이점이 있다. 따라서, 폴리머에 반응성 스퍼터링을 하기 위해서는 표면처리가 중요한 변수가 되며, roll to roll sputter로 ITO 필름을 얻기 위해서는 폭과 길이 방향으로 균일한 막을 얻는 것이 중요하다. 두께 75$\mu\textrm{m}$, 폭 190mm, 길이 400m로 권취된 광학용 Polyethylene terephthalate(PET:Tg:8$0^{\circ}C$)위에 In-10%Sn의 합금타겟과 Unipolar pulsed DC power supply를 사용하여 반응성 마그네트론 스퍼터링 방법으로 0.2m/min의 속도로 연속 스퍼터링 하였다. PET를 Ar/O2 혼합가스로 플라즈마 전처리를 한 후, AFM, XPS를 이용하여 효과를 분석을 하였고, 성막전에 가스방출을 막기 위해 TiO를 코팅하였다. Pilot 연속 생산공정에서 재현성을 위해 PEM(Plasma Emission Monitor)의 optical emission spectroscopy를 이용, 금속과 산화물의 천이구역에서 sprtter된 I/Sn 이온과 산소 이온의 반응에 의한 최적의 플라즈마의 강도값을 입력하여 플라즈마의 radiation을 검출하고, 스퍼터링 공정중 실질적인 in-situ 정보로 이용하였다. PEM을 통하여 In/Sn의 플라즈마 강도변화를 조사하였다. 초기 In/Sn의 플라즈마 강도(intensity)는 강도를 100하여, 산소를 주입한 결과, plasma intensity가 35 줄어들었고, 이때 우수한 ITO 박막을 얻을 수 있었다. Pulsed DC power를 사용하여 아크 현상을 방지하였다. PET 상에 coating 된 ITO 박막의 표면저항과 광투과도는 4-point prove와 spectrophotometer를 이용하여 분석하였고, AES로 박막의 두께에 따른 성분비를 확인하였다. ITO 박막의 광투과도는 산소의 유량과 sputter 된 In/Sn ion의 plasma emission peak에 따라 72%-92%까지 변화하였으며, 저항은 37$\Omega$/$\square$ 이상을 나타내었다. 박막의 Sn/In atomic ratio는 0.12, O/In의 비율은 In2O3의 화학양론적 비율인 1.5보다 작은 1.3을 나타내었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.285-285
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• 2011

EUVL (Extreme Ultra Violet Lithography) is one of competitive lithographic technologies for sub-30nm fabrication of nano-scale Si devices that can possibly replace the conventional photolithography used to make today's microcircuits. Among the core EUVL technologies, mask fabrication is of considerable importance since the use of new reflective optics having a completely different configuration compared to those of conventional photolithography. Therefore new materials and new mask fabrication process are required for high performance EUVL mask fabrication. This study investigated the etching properties of SnO2 (Tin Oxide) as a new absorber material for EUVL binary mask. The EUVL mask structure used for etching is SnO2 (absorber layer) / Ru (capping / etch stop layer) / Mo-Si multilayer (reflective layer) / Si (substrate). Since the Ru etch stop layer should not be etched, infinitely high selectivity of SnO2 layer to Ru ESL is required. To obtain infinitely high etch selectivity and very low LER (line edge roughness) values, etch parameters of gas flow ratio, top electrode power, dc self - bias voltage (Vdc), and etch time were varied in inductively coupled Cl2/Ar plasmas. For certain process window, infinitely high etch selectivity of SnO2 to Ru ESL could be obtained by optimizing the process parameters. Etch characteristics were measured by on scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Detailed mechanisms for ultra-high etch selectivity will be discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.334-334
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• 2012

Transparent oxide semiconductors have recently attracted much attention as channel layer materials due to advantageous electrical and optical characteristics such as high mobility, high stability, and good transparency. In addition, transparent oxide semiconductor can be fabricated at low temperature with a low production cost and it permits highly uniform devices such as large area displays. A variety of thin film transistors (TFTs) have been studied including ZnO, InZnO, and InGaZnO as the channel layer. Recently, there are many studies for substitution of Ga in InGaZnO TFTs due to their problem, such as stability of devices. In this work, new quaternary compound materials, tantalum-indium-tin oxide (TaInSnO) thin films were fabricated by using co-sputtering and used for the active channel layer in thin film transistors (TFTs). We deposited TaInSnO films in a mixed gas (O2+Ar) atmosphere by co-sputtering from Ta and ITO targets, respectively. The electric characteristics of TaInSnO TFTs and thin films were investigated according to the RF power applied to the $Ta_2O_5$ target. The addition of Ta elements could suppress the formation of oxygen vacancies because of the stronger oxidation tendency of Ta relative to that of In or Sn. Therefore the free carrier density decreased with increasing RF power of $Ta_2O_5$ in TaInSnO thin film. The optimized characteristics of TaInSnO TFT showed an on/off current ratio of $1.4{\times}108$, a threshold voltage of 2.91 V, a field-effect mobility of 2.37 cm2/Vs, and a subthreshold swing of 0.48 V/dec.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.11
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• pp.826-830
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• 2013

In this paper, we carried out the investigations of both etch characteristics and mechanisms for the $SnO_2$ thin films in $O_2/BCl_3/Ar$ plasma. The dry etching characteristics of the $SnO_2$ thin films was studied by varying the $O_2/BCl_3/Ar$ gas mixing ratio. We determined the optimized process conditions that were as follows: a RF power of 700 W, a DC-bias voltage of - 150 V, and a process pressure of 2 Pa. The maximum etch rate was 509.9 nm/min in $O_2/BCl_3/Ar$=(3:4:16 sccm) plasma. From XPS analysis, the etch mechanism of the $SnO_2$ thin films in the $O_2/BCl_3/Ar$ plasma can be identified as the ion-assisted chemical reaction while the role of ion bombardment includes the destruction of the metal-oxide bonds as well as the cleaning of the etched surface form the reaction products.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.5
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• pp.254-259
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• 2003

In the fabrication process of transparent conducting thin films of the ATO (antimony-doped tin oxide) on a soda lime glass substrate by a sol-gel dip coating method, the effects of the $SiO_2$ buffer layer formed on the substrate and $N_2$ annealing treatment were investigated by XPS (X-ray photoelectron spectroscopy) analysis. Optical transmittance and electrical resistivity of the 400 nm-thick ATO thin films which were deposited on $SiO_2$ buffer layer/soda lime glass and then annealed under nitrogen atmosphere were 84 % and $5.0\times 10^{-3}\Omega \textrm{cm}$ respectively. The XPS analysis confirmed that a $SiO_2$ buffer layer inhibited Na ion diffusion from the substrate, resulting in prohibiting the formation of a secondary phase such as $Na_2SnO_3$ and SnO and increasing Sb ion concentration and ratio of $Sb^{5+}/Sb^{3+}$ in the film. And it was also found that $N_2$ annealing treatment leads to the reduction of $Sn^{4+}$as well as $Sb^{5+}$ however the reduction of $Sn^{4+}$ is more effective and therefore consequently results in decrease in the electrical resistivity to produce an excellent electrical properties of the film.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.3
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• pp.127-133
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• 2012

To achieve low-cost and high-efficiency of thin-film solar cells applications, the sol-gel method that can be coated on a large area substrate, obtain homogeneous thin films of high purity was used. We studied structural and optical characteristics versus annealing temperature of $Cu_2ZnSnS_4$ which has kesterite structure by substitution low-cost sulfur (S) instead of high-cost selenium (Se). By analyzing XRD patterns, main peak was observed at $2{\theta}=28.5^{\circ}$ when Zn/Sn ratio is 0.8/1.2. And when we observed kesterite structure which has orientation of (112) direction, the more annealing temperature increase the bigger strength of (112) direction is. $Cu_2ZnSnS_4$ thin film showed characteristics of kesterite structure at $550^{\circ}C$. And when we calculated lattice constant, a = 5.5047 and $c=11.014{\AA}$ as same JCPDS (Joint Committee on Powder Standards) data measured. We measured optical transmittance to analyze optical characteristics. Optical transmittance was lower than 65 % at visible ray (${\lambda}=380{\sim}770nm$).