• 한국재료학회지
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• 제14권7호
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• pp.457-461
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• 2004

The thermomechanically treated $Ti-45.4\%Al-4.8\%Nb(at\%)$ alloy was oxidized between 800 and $1000^{\circ}C$ in air, and the oxidation characteristics were studied. The dissolution of Nb in the oxide scale was observed from the TEM study. The Pt marker test revealed that the oxidation process was controlled by the outward diffusion of Ti ions and the inward diffusion of oxygen ions. During oxidation, the evaporation of Nb-oxides was found to occur to a small amount. Niobium tended to pile-up at the lower part of the oxide scale, which consisted primarily of an outer $TiO_2$ layer, and an intermediate $Al_{2}O_{3}-rich$ layer, and an inner mixed layer of ($TiO_{2}+Al_{2}O_{3}$).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.271-271
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• 2012

Many studies have been investigated on high density plasma source (Electron Cyclotron Resonance, Inductively Coupled Plasma, Helicon plasma) for large area source after It is announced that productivity of plasma process depends on plasma density. In this presentation, we will propose the new concept of the multiple source, which consists of a parallel connection of ICP sources and helicon plasma sources. For plasma uniformity, equivalent power (especially, equivalent current in ICP & Helicon) should distribute on each source. We design power feeding line as coaxial transmission line with same length of ground line in each source for equivalent power distribution. And we confirm the equivalent power distribution with simulation and experimental result. Based on basic study, we develop the plasma source for oxidation in semiconductor process. we will discuss the relationship between the processing parameters (With or WithOut magnet, operating pressure, input power ). In ICP, plasma density uniformity is uniform. In ICP with magnet (or Helicon) plasma density is not uniform. As a result, new design (magnet arrangement and gas distributor and etc..) are needed for uniform plasma density in ICP with magnet and Helicon.

• 한국전기전자재료학회논문지
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• 제19권12호
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• pp.1078-1084
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• 2006

Impurity contamination induced by $CF_4\;and\;HBr/Cl_2/O_2$ plasma etching on Si surface was examined by using surface spectroscopes. XPS(x-ray photoelectron spectroscopy) surface analysis showed that F of 0.4 at % exists in the surface layer in the form of Si-F bonding but Br and Cl are below the detection limit $(0.1{\sim}1.0%)$ of the spectroscope. Static-SIMS(secondary ion mass spectrometry) surface analysis showed that the etched Si surface was contaminated with etching gas elements such as H, F, Cl and Br, and they existed to the depth of about $20{\sim}40nm$. The etched Si surface was treated with three different methods that were HF dip, thermal oxidation followed by HF dip and oxygen-plasma oxidation followed by HF dip. They showed an effect in reducing the impurity contamination and the oxygen-plasma oxidation followed by HF dipping method appears to be a little bit more effective.

• 열처리공학회지
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• 제18권1호
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• pp.24-28
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• 2005

New post plasma nitriding can achieve a high uniformity that have been difficult in DC nitriding and have a high productivity comparable to gas nitriding. However, it has not a enough high nitriding potential for a rapid nitriding, because surface activation or ion etching in the general plasma nitriding cannot be expected. Thus, in this study, the effects of pre-treatments with oxidation and reduction gas have been investigated to improve the nitriding kinetics of post plasma nitriding. An effective pre-treatment consisting of oxidation and reduction resulted in the increase of surface energy of STD 11. This induced the surface hardness and the effective nitriding depth of STD 11. It is thought that the increase of the surface energy and the surface area with pre-treatment promote the nucleation of nitriding layer.

• 한국세라믹학회지
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• 제46권3호
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• pp.295-300
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• 2009

The crystal structure of surface coatings on Al1050 alloy by PEO (Plasma Electrolytic Oxidation), were investigated. The electrolyte for PEO was Na-Si-P system solution. The main crystalline phase were $\gamma$-alumina and $\alpha$-alumina. Crystallinity was increased with applied voltage and applied time. The dominant crystalline phase were affected not only chemical composition of Al alloy substrate and electrolyte, but also the +/- ratio of applied voltage.

• 한국재료학회지
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• 제14권10호
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• pp.683-687
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• 2004

The BON thin films were grown on the Si substrate by the RF-PECVD method. When stored at the room temperature, the phase separation or transition of BON thin films occurred on the surface, due to the hydrophilic property of BON. The oxidation of BON thin films occurred mainly by the evaporation of B, O and N. The oxidized BON thin films consisted of an amorphous phase and a bit of the polycrystalline phase.

• 한국표면공학회지
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• 제29권6호
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• pp.773-780
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• 1996

Silicon oxide films were prepared by using five kinds of organosilicon compound as gas sources without oxygen by rf plasma-enhanced CVD (PECVD). UV light was irradiated on a substrate vertically during deposition to enhance film oxidation and ablation of carbon contamination in a deposited films. Films prepared with UV irradiation contained less carbon than those prepared without UV irradiation. The oxidation of the films was improved by UN irradiation. The effect of UV irradiation was, however, not observed when the films were prepared with tetramethy lsilane (TMS) which contained no oxygen atom. Dissociated oxygen atoms from an organosilicon compound were excited in the plasma with UV irradiation around the substrate surface and affected the enhancement of film oxidation and ablation of carbon in the films.

• Corrosion Science and Technology
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• 제5권6호
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• pp.213-217
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• 2006

Titania coatings were prepared on commercially pure Ti by plasma electrolytic oxidation (PEO) method with various electrolytes and process condition. Coatings were formed under galvanostatic condition with several current density values, and the change of applied voltage with process time was recorded. The microstructure of the titania coatings was observed using XRD, SEM, TEM, and the time-voltage diagrams were analyzed in terms of microstructure evolution.

• Corrosion Science and Technology
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• 제8권6호
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• pp.227-231
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• 2009

Mg and Mg alloys have been used for lots of applications, including automobile industry, aerospace, mobile phone and computer parts owing to low density. However, Mg and Mg alloys have a restricted application because of poor corrosion properties. Thus, improved surface treatments are required to produce protective films that protect the substrate from corrosive environments. Environmental friendly Plasma Electrolytic Oxidation (PEO) has been widely investigated on magnesium alloys. PEO process combines electrochemical oxidation with plasma treatment in the aqueous solution. In this study, AZ91 Mg alloys were treated by PEO process in controlling the current with PC condition and treated time, concentration of NaF, NaOH, and $Na_2SiO_3$. The surface morphology and phase composition were analyzed using SEM, EDS and XRD. The potentiodynamic polarization tests were carried out for the analysis of corrosion properties of specimen. Additionally, salt spray tests were carried out to examine and compare the corrosion properties of the PEO treated Mg alloys.

• 한국연소학회지
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• 제11권2호
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• pp.15-21
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• 2006

Characteristics of a plasma reactor for partial oxidation of methane, especially focused on the role and effectiveness of plasma chemistry, are investigated. Partial oxidation of methane is investigated using a rotating arc which is a three dimensional version of a typical gliding arc. Three different modes of operation were found. Each mode shows different reforming performance. The reason for the difference is due to the difference in relative role of thermal and plasma chemistry in overall process. A mode with high temperature results higher methane conversion and hydrogen selectivity in contrast to the mode with lower temperature where poor methane conversion and higher selectivity of $C_2$ species are observed. In this way, we can confirm that by controlling characteristic of process or controlling relative strength of plasma chemistry and thermal chemistry, it is possible to map an optimal condition of reforming process by rotating arc.