• Progress in Superconductivity and Cryogenics
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• v.11 no.2
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• pp.1-6
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• 2009

We report a successful fabrication of $high-J_c\;NdBa_2Cu_3O_{7-{\delta}}$ (NdBCO) films on $SrTiO_3$(STO) (100) substrates by pulsed laser deposition (PLD) in a relatively wide processing window. Under various oxygen pressures controlled by either 1%$O_2$/Ar mixture gas or pure $O_2$ gas, strongly c-axis oriented NdBCO films were grown at the substrate temperature $(T_s)\;of\;800^{\circ}C$ in 800 mTorr with 1%$O_2$/Ar gas and also in 400 and 800 mTorr with pure $O_2$ gas. These samples exhibited $T_c$ values over 90K and $J_c$ values of $2.8-3.5MA/cm^2$ at 77K in self-field (77K, sf). On the other hand, $J_c$ values over $1A/cm^2$ were obtained at the temperature regions of $700-830^{\circ}C$ in 800 mTorr with 1%$O_2$/Ar gas at those of $750-830^{\circ}C$ in 800 mTorr with pure $O_2$ gas. Unlike previous reports, resent results support that the PLD processing window for high-Jc NdBCO films is not narrow.

• Transactions on Electrical and Electronic Materials
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• v.4 no.2
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• pp.29-34
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• 2003

Ferroelectric YMnO$_3$ thin films were etched with Ar/C1$_2$ and CF$_4$/C1$_2$ Plasma. The maximum etch rate of YMnO$_3$ thin film was 300 $\AA$/min at a Cl$_2$/Ar gas mixing ratio of 8/2, an RF power of 800 W, a do bias of-200 V, a chamber pressure of 15 mTorr, and a substrate temperature of 3$0^{\circ}C$. From the X-ray photoelectron spectroscopy (XPS) analysis, yttrium was not only etched by chemical reactions with Cl atoms, but also assisted by Ar ion bombardments in Ar/C1$_2$ plasma. In CF$_4$/C1$_2$ plasma, yttrium formed nonvolatile YF$_{x}$ compounds and remained on and the etched surface of YMnO$_3$. Manganese etched effectively by forming volatile MnCl$_{x}$ and MnF$_{y}$. From the X-ray diffraction (XRD) analysis, the (0004) diffraction peak intensity of the YMnO$_3$ thin film etched in Ar/Cl$_2$ plasma shows lower than that in CF$_4$/Cl$_2$ plasma. It indicates that the crystallinty of the YMnO$_3$ thin film is more easily damaged by the Af ion bombardment than the changes of stoichiometry due to nonvolatile etch by-products.cts.s.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.384-384
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• 2010

The surface reaction characteristics of Zinc Oxide (ZnO) in $Cl_2/BCl_3$/Ar gas ratio using inductively coupled plasma system were investigated. It was found that ZnO etch rate shows a non-monotonic behavior with increasing both Ar fraction in $Cl_2/BCl_3$ plasma, RF power, and gas pressure. The maximum ZnO etch rate of 53 nm/min was obtained for $Cl_2$(3 sccm)/$BCl_3$(16 sccm) /Ar(4 sccm) gas mixture. The chemical state of etched surfaces was investigated with X-ray diffraction (XRD) and the etched surface was investigated to the rms by atomic force microscopy (AFM). From these data, the suggestions on the ZnO etch mechanism were made by secondary ion mass spectrometery (SIMS).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.12
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• pp.959-964
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• 2001

We investigated the etching characteristics of YMnO$_3$ thin films in high-density plasma etching system. In this study, YMnO$_3$ thin films were etched with CF$_4$/Ar gas chemistries in inductively coupled plasma(ICP). Etch rates of YMnO$_3$ increased up to 20% CF$_4$ in CF$_4$/(CF$_4$+Ar), but decreased with furthermore increasing CF$_4$ in CF$_4$/(CF$_4$+Ar). In optical emission spectroscopy (OES) analysis, F radical and Ar* ions in plasma at various gas chemistries decreased with increasing CF$_4$ content. Chemical states of YMnO$_3$ films exposed in plasma were investigated with x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). There is a chemical reaction between metal (Y, Mn) and F and metal-fluorides were removed effectively by Ar ion sputtering. YF$_{x}$, MnF$_{x}$ such as YF, YF$_2$, YF$_3$ and MnF$_3$ were detected using SIMS analysis. The etch slope is about 65$^{\circ}$ and cleasn surface. surface of the etched YMnO$_3$ thin films was investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The etch profile was also investigated by scanning electron microscopy (SEM).EM).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.9
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• pp.611-615
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• 2001

Y$_2$O$_3$ thin films have been proposed as a buffering insulator of metal/ferroelectric/insulator/semiconductor field effect transistor(MFISFET)-type ferroelectric random access memory (FRAM). In this study, $Y_2$O$_3$ thin films were etched with inductively coupled plasma(ICP). The etch rates of $Y_2$O$_3$ and YMnO$_3$, and the selectivity of $Y_2$O$_3$ to YMnO$_3$ were investigated by varying Cl$_2$/(Cl$_2$＋Ar) gas mixing ratio. The maximum etch rate of $Y_2$O$_3$, and the selectivity of $Y_2$O$_3$ to YMnO$_3$ were 302$\AA$/min, and 2.4 at Cl$_2$/(Cl$_2$＋Ar) gas mixing ratio of 0.2 respectively. Optical emission spectroscopy(OES) was used to understand the effects of gas combination on the etch rate of $Y_2$O$_3$ thin film. The surface reaction of the etched $Y_2$O$_3$ thin films was investigated by x-ray photoelectron spectroscopy (XPS). XPS analysis confirmed that there was chemical reaction between Y and Cl. This result was confirmed by secondary ion mass spectroscopy(SIMS) analysis.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1374-1375
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• 2006

Ar/$Cl_2$ 유도결합 플라즈마 (ICP)의 가스 혼합비에 따른 $(Bi_{4-x}La_x)Ti_{3}O_{12}$ 박막의 식각 메커니즘과 식각면에서의 플라즈마 손상을 조사하였다. BLT 박막의 최대식각률은 Ar/$Cl_2$ 플라즈마에서의 Ar 가스 혼합비가 80%일 때 50.8 nm의 값을 보였다. 정전 탐침을 통해 Ar 가스의 혼합비에 따른 전자온도와 전자밀도를 관측하였다. 박막 표면의 X-ray photoemission spectroscopy 분석과 박막의 이력곡선을 통해 BLT 박막의 식각 손상은 Cl 원자와의 반응에 의한 화학적 식각 손상이 BLT 박막 표면에서의 Ar 이온충돌에 의한 물리적 손상보다 더 크다는 것을 확인 할 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.109-109
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• 2000

AC형 PDP에서 보호막은 방전시 내구성(내 sputter)이 약한 유전체를 보호함으로써 panel이 장시간동안 안정된 동작을 하게 하며, 방전시 2차 전자를 많이 방출함으로써 방전전압을 낮추는 기능을 갖는다. 또한 패널의 전압특성을 결정하고 수명을 크게 좌우하며 방전전극을 플라즈마 발광에 의한 이온 스퍼터로부터 보호하고 벽전하에 의한 메모리 기능을 가지도록 하는 역할도 하는 것으로 알려져 있다. 일반적으로 보호막의 재료로는 MgO, ZrO, CeO2등이 있으며 특히 MgO는 보호막으로 널리 쓰이고 있다. 일반적으로 MgO의 증착방법의 전자빔 증착, 스퍼터링, 이온 플레이팅법이 있으며 많은 연구자들이 이러한 증착방법에 성장된 박막들을 연구하고 있다. 그러나 Cs을 이용한 MgO의 증착방법은 그리 널리 알려져 있지는 않다. 따라서 본 연구에서는 Ar/O2/Cs을 이용하여 MgO박막을 sputtering 방법으로 증착하였으며 이들의 특성에 관하여 연구하였다. Target으로는 Mg을 사용하였으며 DC sputtering법으로 MgO를 증착하였다. 기판으로는 실리콘과 유리를 이용하였으며 가스로는 Ar과 O2를 이용하고 Cs의 첨가 유무에 따라 증착하였다. 또한 입력 전력, 공정압력, 그리고 O2 가스량에 따라 박막을 증착하였으며 이에 따른 증착속도, 결정성, 조성비를 $\alpha$-step, XRD, 그리고 XPS를 이용하여 측정하였다. CS 참가할 경우 Ar/O2 가스만을 이용하여 증착했을 때보다 증착속도는 증가하였으며 XRD 분석시 (111), (200) 방향으로 우선 성장하는 것을 관찰할 수 있었다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1248_1249
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• 2009

The $Sr_{0.7}Bi_{2.3}Nb_2O_9$(SBN) thin films are deposited on Pt-coated electrode(Pt/Ti/$SiO_2$/Si) using RF sputtering method with RF power and Ar/$O_2$ ratio. The size of grain of SBN thin films were increased with the increase of Ar/$O_2$ ratio and RF power respectively. Also, the crystallinity of SBN thin films were increased remarkably at RF power and Ar/$O_2$ ratio were 80[W] and 80/20, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.206-209
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• 2003

The purpose of AR and HR coating is acquire the very low reflection rate and the high reflection rate through the deposition of a thin film using the refraction ofmaterial. Basically if the high refractive material and the low refractive material are chosen and the condition for the experiment is determined, then we solve theproject with the optical design and multi thin film coating. First of all, we choose $SiO_2$for the low refractive material and $TiO_2$ for the high refractive material and apply Sputtering System easy to control the refraction rate and excellent in reconstruction to the equipment of thin film multiplication. For the control of the refraction rate and growth rate we modify RF Power and the ratio of Gas(Ar:O2), And we use Ellipsometer for estimation and analysis of the refraction rate and growth rate and AFM&SEM for the analysis of surface and component.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.9
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• pp.695-699
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• 2001

Cerium dioxide (CeO$_2$) was used as the intermediate layer between the ferroelectric thin film and Si substrate in a metal-ferroelectric-semiconductor field effect transistor (MFSFET), to improve the interface property by preventing the interdiffusion of the ferroelectric material and the Si substrate. In this study, CeO$_2$ thin films were etched with a CF$_4$/Ar gas combination in inductively coupled plasma (ICP). The maximum etch rate of CeO$_2$ thin films was 270$\AA$/min under CF$_4$/(CF$_4$+Ar) of 0.2, 600 W/-200V, 15 mTorr, and $25^{\circ}C$. The selectivities of CeO$_2$ to PR and SBT were 0.21, 0.25, respectively. The surface reaction in the etching of CeO$_2$ thin films was investigated with x-ray photoelectron spectroscopy (XPS). There is a chemical reaction between Ce and F. Compounds such as Ce-F$_{x}$ remains on the surface of CeO$_2$ thin films. Those products can be removed by Ar ion bombardment. The results of secondary ion mass spectrometry (SIMS) were consistent with those of XPS. Scanning electron microscopy (SEM) was used to examine etched profiles of CeO$_2$ thin films. The etch profile of over-etched CeO$_2$ films with the 0.5${\mu}{\textrm}{m}$ line was approximately 65$^{\circ}$.>.