• 한국전기전자재료학회논문지
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• 제19권4호
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• pp.373-378
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• 2006

We report on plasma damage free-sputtering technologies for organic light emitting diodes (OLEDs), organic thin film transistor (OTFT) and flexible displays by using a box cathode sputtering (BCS) method. Specially designed BCS system has two facing targets generating high magnetic fields ideally entering and leaving the targets, perpendicularly. This target geometry allows the formation of high-density plasma between targets and enables us to realize plasma damage free sputtering on organic layer without protection layer against plasma. The OLED with Al cathode prepared by BCS shows electrical and optical characteristics comparable to OLED with thermally evaporated Mg-Ag cathode. It was found that OLED with Al cathode layer prepared by BCS has much lower leakage current density ($1{\times}10^{-5}\;mA/cm^2$ at -6 V) than that $(1{\times}10^{-2}{\sim}-10^0\;mA/cm^2)$ of OLED prepared by conventional DC sputtering system. This indicates that BCS technique is a promising electrode deposition method for substituting conventional thermal evaporation and DC/RF sputtering in fabrication process of organic based optoelectronics.

• 전자공학회논문지D
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• 제35D권5호
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• pp.33-39
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• 1998

The BST (Ba$_{1-x}$ Sr$_{x}$TiO$_{3}$)(50/50) thin film has been grown by RF magnetron reactive sputtering and its characteristics such as crystallization, surface roughness, and electrical properties have been investigated with varying the film thickness. The crystallization and surface roughness of BST thin film are investigated by using XRD and AFM, respectively The BST thin film anealed at 800.deg. C for 2 min has pure perovskite structure and good surface roughness of 16.1.angs.. We estimate that the thickness and dielectric constant of interface layer between BST film and electrode are 3nm and 18.9, respectively, by measuring the capacitance with various film thickness. As the film thickness increases form 80nm to 240nm, the dielectric constant at 10kHz increases from 199 to 265 and the leakage current density at 200kV/cm decreases from 0.682.mu.A/cm$^{2}$ to 0.181 .mu.A/cm$^{2}$. In the case of 240nm-thick BST thin film, the charge storage density and leakage current density at 5V are 50.5fC/.mu.m$^{2}$ and 0.182.mu.A/cm$^{2}$, respectively. The values indicate that the BST thin film is a very useful dielectric material for the DRAM capacitor.or.

• 한국세라믹학회지
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• 제51권3호
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• pp.190-196
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• 2014

Flexible $TiO_2$ films were deposited as dielectric materials for high-energy-density capacitors on polyethylene terephthalate (PET) substrates using a roll-to-roll sputtering method. Both the growth behavior and electrical properties of the flexible $TiO_2$ films were dependent on the sputtering pressure and $O_2$/Ar gas ratio during the sputtering process. All $TiO_2$ films had an amorphous structure regardless of the sputtering conditions due to the low substrate temperature. Microstructural characteristics such as the surface morphology and roughness of the films degraded with an increase in the sputtering pressure and $O_2$ gas concentration. The $TiO_2$ films deposited at a low pressure showed better electrical properties than those of films deposited at a high pressure. The $TiO_2$ films prepared at 10 mTorr exhibited a dielectric constant of approximately 90 at 1 kHz and a leakage current density of $5{\sim}6{\times}10^{-7}A/cm^2$ at 3 MV/cm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.53-54
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• 2005

We report on plasma damage free-sputtering technologies for organic light emitting diodes (OLEDs), organic thin rim transistor (OTFT) and flexible displays by using a box cathode sputtering (BCS) method. Specially designed BCS system has two facing targets generating high magnetic fields ideally entering and leaving the targets, perpendicularly. This target geometry allows the formation of high-density plasma between targets and enables us to realize plasma damage free sputtering on organic layer without protection layer against plasma. The OLED with top cathode prepared by BCS shows electrical and optical characteristics comparable to OLED with thermally evaporated Mg-Ag cathode. It was found that TOLED with ITO or IZO top cathode layer prepared by BCS has much lower leakage current density ($1\times10^{-5}$ mA/cm2 at -6V) than that ($1\times10^{-1}\sim10^{\circ}mA/cm^2$)of OLED prepared by conventional DC sputtering system. This indicates that BCS technique is a promising electrode deposition method for substituting conventional thermal evaporation and dc/rf sputtering in fabrication process of organic based optoelectronics.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1311-1315
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• 2016

• 전자공학회논문지D
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• 제36D권6호
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• pp.44-51
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• 1999

High density DRAM의 cell capacitor로 촉망 받고 있는 고유전체 BST박막 커패시터의 저 전계(<0.2MV/cm) 영역에서의 전기전도 현상을 분석하였다. 저 전계 영역에서 Pt/BST/Pt구조의 MIM 커패시터에 일정 전계를 인가한 후 전류를 측정하는 I(t)방법을 이용하여 유전완화전류와 누설전류를 분리해내어 박막의 측정온도 변화, 전계의 크기, 인가방향 변화, 후속 열처리에 따른 BST 박막의 전기전도 기구를 분석하였다. 그 결과, 유전완화전류는 Hoppiong process에 의한 BST박막내부의 trap된 전자들의 이동에 의한 전하재배치로 설명되어지며, 누설전류도 박막내의 trap에 의한 poole-Frenkel process에 의한 것임을 알 수 있었다. 그리고 각 전류성분에 기억하고 있는 trap이 BST박막내의 산호 결핍임을 추정하였다.

• 한국전기전자재료학회논문지
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• 제13권6호
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• pp.493-501
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• 2000

The microstructure and electrical properties of ZnO-Pr$_{6}$/O$_{11}$-CoO-Er$_{2}$/O$_{3}$ based varistors were investigated with Er$_{2}$/O$_{3}$ additive content of the range 0.0 to 2.0 mol%. Most of the added Er$_{2}$/O$_{3}$ were segregated at the nodal points and grain boundaries and it coexisted with Pr$_{6}$/O$_{11}$ in the bulk intergranular layer. The average grain size was decreased in the range of 7.44 to 5.62${\mu}{\textrm}{m}$ at 130$0^{\circ}C$ and 18.36 to 9.11 at 135$0^{\circ}C$ with increasing Er$_{2}$/O sub 3/ additive content. The density of ceramics was in the range 4.87 to 5.08 g/cm$^3$ at 130$0^{\circ}C$ and 5.35 to 5.62 g/cm$^3$at 135$0^{\circ}C$. At 130$0^{\circ}C$ the varistors without Er$_{2}$/O$_{3}$ exhibited 29.66 in the nonlinear exponent and 28.23 $\mu$A in the leakage current whereas the varistors with 0.5 mol% Er$_{2}$/O$_{3}$ exhibited a high nonlinearity which is 52.78 in thenonlinear exhibited and 9.75 $\mu$A in the leakage current. At 135$0^{\circ}C$ the varistors without Er$_{2}$/O$_{3}$ exhibited a very poor nonlinearity indicating 2.08 in the nonlinear exponent and 133.79 $\mu$A in the leakage current whereas the varistors with 1.0mol% Er$_{2}$/O$_{3}$ exhibited a relatively high nonlinearity which is 36.79 in the nonlinear exponent and 5.92 $\mu$A in the leakage current. Therefore Er$_{2}$/O$_{3}$ was additive which greatly improve the nonlinearity. It is believed that ZnO-0.5 mol% Pr$_{6}$/O$_{11}$-1.0 mol% CoO-0.5 mol% Er$_{2}$/O$_{3}$ based ceramicss will be usefully used as a basic composition to develop the advanced pr$_{6}$/O$_{11}$-based ZnO varistors.ristors.ristors.

• 한국전기전자재료학회논문지
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• 제16권12S호
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• pp.1175-1180
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• 2003

Transformer Coupled Plasma Chemical Vapor Deposited (TCP-CVD) silicon nitride (SiNx) is widely used as a gate dielectric material for thin film transistors (TFT). This paper reports the SiNx films, grown by TCP-CVD at the low temperature (30$0^{\circ}C$). Experimental investigations were carried out for the optimization o(SiNx film as a function of $N_2$/SiH$_4$ flow ratio varying ,3 to 50 keeping rf power of 200 W, This paper presents the dielectric studies of SiNx gate in terms of deposition rate, hydrogen content, etch rate and leakage current density characteristics lot the thin film transistor applications. And also, this work investigated means to decrease the leakage current of SiNx film by employing $N_2$ plasma treatment. The insulator layers were prepared by two step process; the $N_2$ plasma treatment and then PECVD SiNx deposition with SiH$_4$, $N_2$gases.

• 한국통신학회논문지
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• 제15권3호
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• pp.252-259
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• 1990

本 論文은 기존 LOCOS工程의 張點을 모두 겸비한 側面璧 SWAMI 技術에 대한 새로운 構造를 提示한다. 새로운 SWAMI공정은 순수 窒化膜 壓力과 體積 膨腸에 기인한 壓力을 크게 줄이기 위해서 側面璧 주위에 얇은 질화막과 反應性이온 飾刻으로 기울어진 실리콘 측면벽을 結合시켰따. 製作된 結果에 의하면, 缺陷이 없는 완전히 새부리 모양이 形成되지 않는 局地的 酸化 공정은 기울어진 面의 異方性 산화 隔離에 의해 實現시킬 수 있었다. 추가적인 마스크 段階는 要求되지 않는다. 이 工程에서 PN 다이오드의 漏泄電流는 기존 LOCOS 공정 보다 減少되었다. 한편 가장자리 部位는 漏泄電流 密度에서 평편한 接合 부위 보다 높게 分析되었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권1호
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• pp.34-39
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• 2006

In high-voltage devices such as thyristor, beveling is mostly used junction termination method to reduce the surface electric field far below the bulk electric field and to expand the depletion region thus that breakdown occurs in the bulk of the device rather than at the surface. However, coating material used to protect the surface of the device contain so many charges which affect the electrical characteristics of the device. And device reliability is also affected by this charge. Therefore, it is needed to analyze the effect of surface charge on electrical characteristics of the device. In this paper, we analyzed the breakdown voltage and leakage current characteristics of the thyristor as a function of the amount of surface charge density. Two dimensional process simulator ATHENA and two-dimensional device simulator ATLAS is used to analyze the surface charge effects.