• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.31 no.6
• /
• pp.276-281
• /
• 2021

In order to manufacture a semiconductor circuit, etching, cleaning, and deposition processes are repeated. During these processes, the inside of the processing chamber is exposed to corrosive plasma. Therefore, the coating of the inner wall of the semiconductor equipment with a plasma-resistant material has been attempted to minimize the etching of the coating and particle contaminant generation. In this study, we synthesized yttrium oxyfluoride (YOF) powder by a solid-state reaction using Y₂O₃ and YF₃ as raw materials. Mixing ratio of the Y₂O₃ and YF₃ was varied from 1.0:1.0 to 1.0:1.6. Effects of the mixing ratio on crystal structure and microstructure of the synthesized YOF powder were investigated using XRD and FE-SEM. The synthesized YOF powder was successfully applied to plasma spray coating process on Al substrate.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.62-62
• /
• 2015

In this study, we study the effects of CF4 plasma treatment on the characteristics of enhancement mode (E-mode) AlGaN/GaN high electron mobility transistors (HEMTs). The CF4 plasma is generated by inductively coupled plasma reactive ion etching (ICP-RIE) system. The CF4 gas is decomposed into fluorine ions by ICP-RIE and then fluorine ions will effect the AlGaN/GaN interface to inhibit the electron transport of two dimension electron gas (2DEG) and increase channel resistance. The CF4 plasma method neither like the recessed type which have to utilize Cl2/BCl3 to etch semiconductor layer nor ion implantation needed high power to implant ions into semiconductor. Both of techniques will cause semiconductor damage. In the experiment, the CF4 treatment time are 0, 50, 100, 150, 200 and 250 seconds. It was found that the devices treated 100 seconds showed best electric performance. In order to prove fluorine ions existing and CF4 plasma treatment not etch epitaxial layer, the secondary ion mass spectrometer confirmed fluorine ions truly existing in the sample which treatment time 100 seconds. Moreover, transmission electron microscopy showed that the sample treated time 100 seconds did not have etch phenomena. Atomic layer deposition is used to grow Al2O3 with thickness 10, 20, 30 and 40 nm. In electrical measurement, the device that deposited 20-nm-thickness Al2O3 showed excellent current ability, the forward saturation current of 210 mA/mm, transconductance (gm) of 44.1 mS/mm and threshold voltage of 2.28 V, ION/IOFF reach to 108. As IV concerning the breakdown voltage measurement, all kinds of samples can reach to 1450 V.

• Textile Coloration and Finishing
• /
• v.27 no.1
• /
• pp.18-26
• /
• 2015

para-aramid fibers were treated by atmosphere air plasma to improve the interfacial adhesion. The wettability of plasma-treated aramid fiber was observed by means of dynamic contact angle surface free energy measurement. Surface roughness were investigated with the help of scanning electron microscopy and atomic force microscopy. The tensile test of aramid fiber roving was carried out to determine the effect of plasma surface treatments on the mechanical properties of the fibers. A pull-out force test was carried out to observe the interfacial adhesion effect with matrix material. It was found that surface modification and a chemical component ratio of the aramid fibers improved wettability and adhesion characterization. After oxygen plasma, it was indicated that modified the surface roughness of aramid fiber increased mechanical interlocking between the fiber surface and vinylester resin. Consequently the oxygen plasma treatment is able to improve fiber-matrix adhesion through excited functional group and etching effect on fiber surface.

• Transactions on Electrical and Electronic Materials
• /
• v.14 no.3
• /
• pp.133-138
• /
• 2013

Acrylonitrile-butadiene-styrene (ABS) plastic is a polymer material extensively used in electrical and electronic applications. Nickel (Ni) thin film was deposited on ABS by electroless plating, after its surface was treated and modified with atmospheric plasma generated by means of dielectric barrier discharges (DBDs) in air. The method in this study was developed as a pre-treatment for electroless plating using DBDs, and is a dry process featuring fewer processing steps and more environmentally friendliness than the chemical method. After ABS surfaces were modified, surface morphologies were observed using a scanning electron microscope (SEM) to check for any physical changes of the surfaces. Cross-sectional SEM images were taken to observe the binding characteristics between metallic films and ABS after metal plating. According to the SEM images, the depths of ABS by plasma are shallow compared to those modified by chemically treatment. The static contact angles were measured with deionized (DI) water droplets on the modified surfaces in order to observe for any changes in chemical activities and wettability. The surfaces modified by plasma showed smaller contact angles, and their modified states lasted longer than those modified by chemical etching. Adhesion strengths were measured using 3M tape (3M 810D standard) and by 90° peel-off tests. The peel-off test revealed the stronger adhesion of the Ni films on the plasma-modified surfaces than on the chemically modified surfaces. Thermal shock test was performed by changing the temperature drastically to see if any detachment of Ni film from ABS would occur due to the differences in thermal expansion coefficients between them. Only for the plasma-treated samples showed no separation of the Ni films from the ABS surfaces in tests. The adhesion strengths of metallic films on the ABS processed by the method developed in this study are better than those of the chemically processed films.

• Transactions on Electrical and Electronic Materials
• /
• v.4 no.2
• /
• pp.29-34
• /
• 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 Vacuum Society Conference
• /
• 2012.02a
• /
• pp.463-463
• /
• 2012

ITRS (international technology roadmap for semiconductors)에 따르면 MOS(metal-oxide-semiconductor)의 CD (critical dimension)가 45 nm node이하로 줄어들면서 poly-Si/$SiO_2$를 대체할 수 있는 poly-Si/metal gate/high-k dielectric이 대두된다고 보고하고 있다. 일반적으로 high-k dielectric를 식각시 anisotropic 한 식각 형상을 형성시키기 위해서 plasma를 이용한 RIE (reactive ion etching)를 사용하고 있지만 PIDs (plasma induced damages)의 하나인 PIED (plasma induced edge damage)의 발생이 문제가 되고 있다. PIED의 원인으로 plasma의 direct interaction을 발생시켜 gate oxide의 edge에 trap을 형성시키므로 그 결과 소자 특성 저하가 보고되고 있다. 그러므로 본 연구에서는 이에 차세대 MOS의 high-k dielectric의 식각공정에 HDP (high density plasma)의 ICP (inductively coupled plasma) source를 이용한 원자층 식각 장비를 사용하여 PIED를 줄일 수 있는 새로운 식각 공정에 대한 연구를 하였다. One-monolayer 식각을 위한 1 cycle의 원자층 식각은 총 4 steps으로 구성 되어 있다. 첫 번째 step은 Langmuir isotherm에 의하여 표면에 highly reactant atoms이나 molecules을 chemically adsorption을 시킨다. 두 번째 step은 purge 시킨다. 세 번째 step은 ion source를 이용하여 발생시킨 Ar low energetic beam으로 표면에 chemically adsorbed compounds를 desorption 시킨다. 네 번째 step은 purge 시킨다. 결과적으로 self limited 한 식각이 이루어짐을 볼 수 있었다. 실제 공정을 MOS의 high-k dielectric에 적용시켜 metal gate/high-k dielectric CMOSFETs의 NCSU (North Carolina State University) CVC model로 구한 EOT (equivalent oxide thickness)는 변화가 없으면서 mos parameter인 Ion/Ioff ratio의 증가를 볼 수 있었다. 그 원인으로 XPS (X-ray photoelectron spectroscopy)로 gate oxide의 atomic percentage의 분석 결과 식각 중 발생하는 gate oxide의 edge에 trap의 감소로 기인함을 확인할 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.171-174
• /
• 2002

The barium strontium titannate (BST) thin films were etched in $CF_{4}/Ar$ inductively coupled plasma (ICP). The high etch rate obtained at a $CF_{4}(20%)/Ar(80%)$ and the etch rate in pure argon was twice higher than that in pure $CF_{4}$. This indicated that BST etching is sputter dominant process. It is impossible to avoid plasma-induced damages by the energetic particles in the plasma and the nonvolatile etch products. The plasma damages were evaluated in terms of leakage current density, residues on the etched sample, and the changes of roughness. After the BST thin films exposed in the plasma, the leakage current density and roughness increases. In addition, there are appeared a nonvolatile etch byproductsand from the result of X-ray photoelectron spectroscopy (XPS). After annealing at ${600^{\circ}C}$ for 10 min in $O_{2}$ ambient, the increased leakage current density, roughness and nonvolatile etch byproducts reduced. From the this results, the plasma induced damage recovered by annealing process owing to the relaxation of lattice mismatches by Ar ions and the desorption of metal fluorides in high temperature.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.393-393
• /
• 2010

The biocompatibility of materials used for biomedical applications depends on chemical composition, mechanical stiffness, surface energy, and roughness. The plasma treatment and etching process is a very important technology in the biomedical fields due to possibility of controlling the surface chemistry and properties of materials. In this work, $N_2/H_2$ plasma were treated on single-walled carbon nanotubes (SWCNTs) paper and characterization of treated SWCNTs paper was carried out. Also we investigated neurite outgrowth from SH-SY5Y on treated SWCNTs paper. The results indicated that $N_2/H_2$ plasma-modified SWCNTs paper enhanced neuronal cell adhesion, viability, neurite outgrowth and branching in vitro and exerted a positive role on the health of neural cells.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2011.11a
• /
• pp.31-31
• /
• 2011

섬유제품은 대부분은 흡수성 또는 흡유성을 가지고 있어 물이나 기름이 등을 쉽게 흡수하는 성질이 있다. 이러한 성질 때문에 물이나 기름 등의 접촉에 의한 얼룩과 오염이 잘 되는 단점을 가지고 있다. 이러한 문제점을 해소하기 위하여 원단에 대한 발수, 발유, 방오가공 등이 연구되어 왔으며 섬유의 고유한 화학적, 기계적 물성을 유지하면서 표면과 이면이 다른 특성을 가지도록 유도하여 기능성을 부여하는 편면가공을 주목을 받게 되었다. 본 연구에서는 불소계로 발수처리 된 PET직물에 저온 Plasma와 Sputter을 이용하여 직물의 한쪽 면에는 친수성과 다른 면에는 발수성이 동시에 나타나는 편발수에 관한 실험을 했다. 불소계로 발수처리 된 시료와 저온 Plasma처리된 시료와 Sputter처리된 시료(처리면, 미처리면)를 접촉각 5회 측정하여 평균값을 나타냈다. 발수처리 된 시료의 평균 접촉각 값은 $149^{\circ}$이며, 저온 Plasma의 평균값은 $45^{\circ}$(처리면) $128^{\circ}$(미처리면), Sputter는 $74^{\circ}$(처리면) $144^{\circ}$(미처리면) 으로 가공처리 된 시료에는 양면의 접촉각이 확연한 차이가 나타난 걸로 미루어 보아 편면발수효과가 얻어졌다고 판단된다. SEM 측정을 통하여 관찰한 경우, 발수처리 된 시료에서는 불소계 발수제의 흔적이 보였다. 저온 Plasma, Sputter 처리된 시료에서는 처리시간이 높아짐에 따라서 시료표면에 코팅된 불소계 발수제 막들이 점점 파괴되는 것을 관찰할 수 있었다. 그리고 건식가공으로 인하여 처리된 표면에는 Etching작용이 일어나 표면적이 넓어져 친수화가 일어난 것으로 생각된다. 이처럼 저온 Plasma가공과 Sputter가공으로 편발수를 얻을 수 있다면 에너지 절약, 처리공정과 시간단축 등 여러 가지 장점이 기대된다.

• Proceedings of the Korea Crystallographic Association Conference
• /
• 2007.11a
• /
• pp.47-47
• /
• 2007