• Journal of the Korean institute of surface engineering
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• v.49 no.4
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• pp.376-381
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• 2016

The effects of ICP (Inductively Coupled Plasma) power, ranging from 0 to 200 W, on the crystal structure, microstructure, surface roughness and mechanical properties of magnetron sputtered VN coatings were systematically investigated with FE-SEM, AFM, XRD and nanoindentation. The results show that ICP power has a significant influence on coating microstructure and mechanical properties of VN coatings. With the increasing of ICP power, coating microstructure evolves from a porous columnar structure to a highly dense one. Average crystal grain size of single phase cubic fcc VN coatings was decreased from 10.1 nm to 4.0 nm with increase of ICP power. The maximum hardness of 28.2 GPa was obtained for the coatings deposited at ICP power of 200 W. The smoothest surface morphology with Ra roughness of 1.7 nm was obtained from the VN coating sputtered at ICP power of 200 W.

• Journal of the Korean institute of surface engineering
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• v.45 no.3
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• pp.123-129
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• 2012

Nanocrystalline CrN coatings were fabricated by DC and ICP (inductively coupled plasma) assisted magnetron sputtering techniques. The effect of ICP power, ranging from 0 to 500 W, on coating microstructure, preferred orientation mechanical properties were systematically investigated with HR-XRD, SEM, AFM and nanoindentation. The results show that ICP power has an significant influence on coating microstructure and mechanical properties of CrN coatings. With the increasing of ICP power, coating microstructure evolves from the columnar structure of DC process to a highly dense one. Grain size of CrN coatings were decreased from 11.7 nm to 6.6 nm with increase of ICP power. The maximum nanohardness of 23.0 GPa was obtained for the coatings deposited at ICP power of 500 W. Preferred orientation in CrN coatings also vary with ICP power, exerting an effective influence on film nanohardness.

• Journal of the Korean institute of surface engineering
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• v.54 no.6
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• pp.348-356
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• 2021

In this study, optical diagnosis of plasma was performed for nitrogen doping in graphene using a horizontal inductively coupled plasma (ICP) system. Graphene was prepared by mechanical exfoliation and the ICP system using nitrogen gas was ignited for plasma-induced and defect-suppressed nitrogen doping. In order to derive the optimum condition for the doping, plasma power, working pressure, and treatment time were changed. Optical emission spectroscopy (OES) was used as plasma diagnosis method. The Boltzmann plot method was adopted to estimate the electron excitation temperature using obtained OES spectra. Ar ion peaks were interpreted as a reference peak. As a result, the change in the concentration of nitrogen active species and electron excitation temperature depending on process parameters were confirmed. Doping characteristics of graphene were quantitatively evaluated by comparison of intensity ratio of graphite (G)-band to 2-D band, peak position, and shape of G-band in Raman profiles. X-ray photoelectron spectroscopy also revealed the nitrogen doping in graphene.

• Journal of Power Electronics
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• v.19 no.3
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• pp.655-664
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• 2019

In order to analyze the nonlinear phenomena of the bifurcation and chaos caused by the switching of nonlinear switching devices in inductively coupled power transfer (ICPT) systems, a Jacobian matrix model, based on discrete mapping numerical modeling, is established to judge the system stability of the periodic closed orbit and to study the nonlinear behavior of Hopf bifurcation in a system under full resonance. The general flow of the parameter design, based on the stability principle for ICPT systems, is proposed to avoid the chaos and bifurcation phenomena caused by unreasonable parameter selection. Firstly, based on the state equation of SS-type compensation, a three-dimensional bifurcation diagram with the coupling coefficient as the bifurcation parameter is established with a numerical simulation to observe the nonlinear phenomena in the system. Then Filippov's method based on a Jacobian matrix model is adopted to deduce the boundary of stable operation and to judge the type of the bifurcation in the system. Then the general flow of the parameter design based on the stability principle for ICPT systems is proposed through the above analysis to realize stable operation under the conditions of weak coupling. Finally, an experimental platform is built to confirm the correctness of the numerical simulation and modeling.

• Corrosion Science and Technology
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• v.20 no.3
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• pp.112-117
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• 2021

Inductively coupled plasma magnetron sputtering (ICPMS) has the advantage of being able to dramatically improve coating properties by increasing the plasma ionization rate and the ion bombardment effect during deposition. Thus, this paper presents the comparative results of CrN films deposited by direct current magnetron sputtering (dcMS) and ICPMS systems. The structure, microstructure, and mechanical and corrosive properties of the CrN coatings were investigated by X-ray diffractometry, scanning electron microscopy, nanoindentation, and corrosion-resistance measurements. The as-deposited CrN films by ICPMS grew preferentially on a 200 plane compared to dcMS on a 111 plane. As a result, the films deposited by ICPMS had a very compact microstructure with high hardness. The nanoindentation hardness reached 19.8 GPa, and 13.5 GPa by dcMS. The corrosion current density of CrN film prepared by ICPMS was about 9.8 × 10^-6 mA/cm², which was 1/470 of 4.6 × 10^-3 mA/cm², the corrosion current density of CrN film prepared by dcMS.

• Journal of the Korean institute of surface engineering
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• v.55 no.2
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• pp.70-76
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• 2022

In this paper, we compared the properties of the chromium nitride (CrN) films prepared by inductively coupled plasma magnetron sputtering (ICPMS). As a comparison, CrN film prepared by a direct current magnetron sputtering (dcMS) is also studied. The crystal structure, surface and cross-sectional microstructure and composite properties of the as-deposited CrN films are compared by x-ray diffraction, field emission scanning electron microscopy, nanoindentation tester and corrosion resistance tester, respectively. It is found that the as-deposited CrN films by ICPMS grew preferentially on (200) plane when compared with that by dcMS on (111) plane. As a result, the films deposited by ICPMS have a very compact microstructure with high hardness: the nanoindentation hardness reached 19.8 GPa and 13.5 GPa by dcMS, respectively. Besides, the residual stress of CrN films prepared by ICPMS is also relatively large. After measuring the corrosion resistance, the corrosion current of films prepared by ICPMS was three order of magnitude smaller than that of CrN films deposited by dcMS.

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.214-217
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• 2022

The effect of inductively coupled plasma (ICP) treatment with O₂ gas on the surface properties of poly(ether sulfone) (PES) was investigated. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical characteristics of the O₂ plasma-treated PES films. The surface roughness of the pristine and O₂ plasma-treated PES films for different RF powers of the ICP was determined using an atomic force microscope (AFM). The contact angles of the PES films were also measured, using which the surface free energies were calculated. The O1s XPS spectra of the PES films revealed that the number of polar functional groups increased following the O₂ plasma treatment. The AFM analysis showed the average surface roughness increased from 1.01 to 4.48 nm as the RF power of the ICP was increased. The contact angle measurements revealed that the PES films became more hydrophilic as the RF power of the ICP was increased. The total surface energy increased with the RF power of the ICP, resulting from the increased polar energy component.

• Applied Microscopy
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• v.50
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• pp.7.1-7.10
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• 2020

Tantalum nitride (TaN_x) thin films were grown utilizing an inductively coupled plasma (ICP) assisted direct current (DC) sputtering, and 20-100% improved microhardness values were obtained. The detailed microstructural changes of the TaN_x films were characterized utilizing transmission electron microscopy (TEM), as a function of nitrogen gas fraction and ICP power. As nitrogen gas fraction increases from 0.05 to 0.15, the TaN_x phase evolves from body-centered-cubic (b.c.c.) TaN_0.1, to face-centered-cubic (f.c.c.) δ-TaN, to hexagonal-close-packing (h.c.p.) ε-TaN phase. By increasing ICP power from 100 W to 400 W, the f.c.c. δ- TaN phase becomes the main phase in all nitrogen fractions investigated. The higher ICP power enhances the mobility of Ta and N ions, which stabilizes the δ-TaN phase like a high-temperature regime and removes the micro-voids between the columnar grains in the TaN_x film. The dense δ-TaN structure with reduced columnar grains and micro-voids increases the strength of the TaN_x film.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.197-197
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• 2012

Device 제작에 사용된 graphene은 일반적인 lithography 공정에서 resist residue에 의한 오염을 피할 수 없으며 이로 인하여 graphene의 pristine한 성질을 잃어버린다. 본 연구에서는 graphene을 저밀도의 argon inductively coupled plasma (Ar-ICP)를 통해 처리함으로서 graphene based back-gated field effect transistor (G-FET)의 특성변화를 유도한 결과에 대해서 보고한다. Argon capacitively coupled plasma (Ar-CCP)은 에 노출된 graphene은 강한 ion bombardment energy로 인하여 쉽게 planar C-C ${\pi}$ bonding (bonding energy: 2.7 eV)이 breaking되어 graphene의 defect이 발생되었다. 하지만 우리의 경우 저밀도의 Ar-ICP가 적용될 때 graphene의 defect이 제한되며 이와 동시에 contamination 만을 제거할 수 있었다. 소자의 전기적 측정 (Gsd-Vbg)을 통하여 contamination으로 인하여 p-doping된 graphene은 pristine 상태로 회복되었으며 mobility도 회복됨이 확인되었다. Ar-ICP를 이용한 graphene cleaning 방법은 저온공정, 대면적 공정, 고속공정을 모두 만족시키며 thermal annealing, electrical current annealing을 대체하여 graphene 기반 소자를 생산함에 있어 쉽고 빠르게 적용할 수 있는 강점이 있다.

• Journal of the Korean institute of surface engineering
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• v.37 no.3
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• pp.169-174
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• 2004

MgO thin films were reactively deposited using an internal inductively coupled plasma assisted sputtering method varying reactive gas ratio to get stoichiometric film composition, and bipolar dc substrate bias to suppress micro arcs. The minimum frequency required for arc suppression was about 10KHz depending on ICP power. Their crystallinity was analyzed using X-ray diffraction and surface morphology using AFM. The surface was very smooth with rms roughness less than 0.42nm. The preferred orientation of the films were changing from (200) to bulk-like characteristics as Ar: $O_2$ratio was controlled to 10 : 2. Optical emission spectroscopy revealed that there were two distinct discharge modes: a blue one and a green one, where enhanced emission from Ar and Mg were observed. This cannot simply be understood by metallic or oxide mode of reactive sputtering due to ICP coupled to magnetron discharge.