• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.59.2-59.2
• /
• 2015

Modification of film structure and properties in inductively-coupled plasma (ICP) assisted dc and pulsed dc sputtering has been reported by Oya and Kusano [1] and by Sakamoto, Kusano, and Matsuda [2], showing drastic changes in films structure and properties by the ICP assistance in particular to the pulsed dc discharge. Although mechanisms involved in the modification has been reported to be the increase in energy transferred to the substrate, details of effects of low-energy ion bombardment on the modification and origin of an anomalous increase in the ion quantity by the ICP assistance to the pulsed dc discharge have not been discussed. In this presentation, mechanisms involved in film structure and property modification in ICP assisted dc and pulsed dc sputtering, in which a number of low-energy ions are formed, will be discussed based on ion energy distribution as well as effectiveness of energy transfer to the substrate by low energy particles [3]. The results discussed in this presentation will emphasize the fact that the energetic particles playing an important role in the film structure modification are those to be deposited, but not those of inert gas, when their energies range in less than 100 eV in the pressure range of magnetron sputtering.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2008.11a
• /
• pp.45-46
• /
• 2008

Hard coatings of TiN which exhibit a large variation in their electrical resistivities, have been prepared in magnetron sputtering system using bipolar pulsed DC generator. TiN coatings have also been prepared using a DC generator in the same sputtering system under identical deposition conditions. Microstructural, Mechanical, Crystallographic properties of TiN films using continuous and bipolar pulsed DC generators were examined. Field emission scanning microscope and Nanoindenter have been used to characterize the coatings.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2001.11a
• /
• pp.35-35
• /
• 2001

agnesium Oxide (MgO) with a NaCI structure is well known to exhibit high secondary electron emission, excellent high temperature chemical stability, high thermal conductance and electrical insulating properties. For these reason MgO films have been widely used for a buffer layer of high $T_c$ superconducting and a protective layer for AC-plasma display panels to improve discharge characteristics and panel lifetime. Up to now MgO films have been synthesized by lE-beam evaporation, Molecular Beam Epitaxy (MBE) and Metalorganic Chemical Vapor Deposition (MOCVD), however there have been some limitations such as low film density and micro-cracks in films. Therefore magnetron sputtering process were emerged as predominant method to synthesis high density MgO films. In previous works, we designed and manufactured unbalanced magnetron source with high power density for the deposition of high quality MgO films. The magnetron discharges were sustained at the pressure of O.lmtorr with power density of $110W/\textrm{cm}^2$ and the maximum deposition rate was measured at $2.8\mu\textrm{m}/min$ for Cu films. In this study, the syntheses of MgO films were carried out by unbalanced magnetron sputtering with various $O_2$ partial pressure and specially target power densities, duty cycles and frequency using pulsed DC power supply. And also we investigated the plasma states with various $O_2$ partial pressure and pulsed DC conditions by Optical Emission Spectroscopy (OES). In order to confirm the relationships between plasma states and film properties such as microstructure and secondary electron emission coefficient were analyzed by X-Ray Diffraction(XRD), Transmission Electron Microscopy(TEM) and ${\gamma}-Focused$ Ion Beam (${\gamma}-FIB$).

• Proceedings of the Korean Vacuum Society Conference
• /
• 2007.02a
• /
• pp.87-87
• /
• 2007

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2011.05a
• /
• pp.264-266
• /
• 2011

• Journal of the Korean Ceramic Society
• /
• v.50 no.6
• /
• pp.390-395
• /
• 2013

Nanocrystalline CrN films were deposited on Si (100) substrates by means of asymmetric pulsed DC reactive magnetron sputtering. We investigated the growth behavior, corrosion resistance and mechanical properties of CrN films with a change in the duty cycle and pulse frequency. The grain size of the CrN films decreased from 25.4 nm to 11.2 nm upon a decrease in the duty cycle. The corrosion potentials for the CrN films by DC sputtering was approximately - 0.6 V, and it increased to - 0.3 V in the CrN films which underwent pulsed sputtering. The nanoindentation hardness of the CrN films also increased with a decrease in the duty cycle. This enhancement of the corrosion resistance and mechanical properties of pulsed sputtered CrN films could be attributed to the densification and surface smoothness of the microstructure of the films.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.14 no.4
• /
• pp.145-150
• /
• 2004

We have investigated the structural, electrical and optical properties of Al-doped ZnO (AZO) thin films grown on glass substrate by pulsed DC magnetron sputtering as functions of pulse frequency and substrate temperature. A highly c-axis oriented AZO thin film is grown in perpendicular to the substrate when pulse frequency of 30 kHz and substrate temperature of $400^{\circ}C$ was applied. Under this optimized growth condition, the resistivity of AZO thin films exhibited $7.40\times 10^{-4}\Omega \textrm{cm}$. This indicated that the decrease of film resistivity resulted from the improvement of film crystallinity. The optical transmittance spectra of the films showed a very high transmittance of 85∼90 % in the visible wavelength region and exhibited the absorption edge of about 350 nm. The results show the potential application for transparent conductivity oxide (TCO) thin films.

• Transactions on Electrical and Electronic Materials
• /
• v.17 no.6
• /
• pp.351-354
• /
• 2016

The mechanical properties of ITO films such as adhesion and internal stress are very important for the commercial application of solar cell devices. We report high quality pulsed DC magnetron sputtered ITO films deposited on silicon and glass substrates with low resistivity and high transmittance for various working pressures ranging from 0.96 to 3.0 mTorr. ITO films showed the lowest resistivity of $2.68{\times}10^{-4}{\Omega}{\cdot}cm$, high hall mobility of $46.89cm^2/V.s$, and high transmittance (>85%) for the ITO films deposited at a low working pressure of 0.99 mTorr. The ITO films deposited at a low working (0.96 mTorr) pressure had both amorphous and polycrystalline structures and were found to have compressive stress while the ITO films deposited at higher temperature than 0.99 mTorr was mixture of amorphous and polycrystalline and was found to have tensile stress.

• Journal of Magnetics
• /
• v.17 no.4
• /
• pp.245-250
• /
• 2012

Ferromagnetic resonance and X-ray specular reflectivity measurements were performed on $Ni_{81}Fe_{19}/Ir_{20}Mn_{80}/Co_{90}Fe_{10}$ exchange bias trilayers, which were grown using the pulsed-DC magnetron sputtering technique on Si(100)/$SiO_2$(1000 nm) substrates, to investigate the evolution of the interface roughness and exchange bias and their dependence on the NiFe layer thickness. The interface roughness values of the samples decrease with increasing NiFe thickness. The in-plane ferromagnetic resonance measurements indicate that the exchange bias field and the peak-to-peak line widths of the resonance curves are inversely proportional to the NiFe thickness. Furthermore, both the exchange bias field and the interface roughness show almost the same dependence on the NiFe layer thickness. The out-of plane angular dependent measurements indicate that the exchange bias arises predominantly from a variation of exchange anisotropy due to changes in interfacial structure. The correlation between the exchange bias and the interface roughness is discussed.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.322-322
• /
• 2011

Transparent Conductive Oxide (TCO) 박막은 디스플레이 산업에 낮은 면저항 및 높은 광투과성으로 없어서는 안 될 중요한 물질로 많은 선행연구가 진행되어져 왔다. 하지만 전 세계적으로 플라즈마와 TCO박막의 특성과의 상관관계에 대한 연구가 부족하여, 디바이스 업계에서 요구하는 수준에 미치지 못하고 있다. 본 연구에서는 저온 공정이 가능한 dual pulsed magnetron sputtering을 이용해 TCO박막을 합성하고 플라즈마 특성 변화에 따른 TCO 박막의 상관관계를 규명 하고자 한다. Dual pulsed magnetron의 자장에 의해 구속되는 플라즈마 내의 이온 종들과 이온과 중성자의 비율관계를 optical emission spectroscopy (OES)로 확인 하였고, 기판 전류 및 기판 온도 측정, Langmuir probe를 통한 플라즈마 특성 분석을 통하여 플라즈마와 특성과 박막 성장과의 상관관계에 대하여 규명 하였다. 전자 온도는 1.25 eV에서 2.46 eV 증가하는 것을 확인할 수 있었으며, 이온 밀도는 $1.7{\times}109/cm^3$에서 $2.2{\times}109/cm^3$ 증가하는 것을 확인하였다. 이러한 플라즈마 밀도가 증가함에 따라 박막은 비정질에서 다결정질로 바뀌면서 전기이동도는 증가하고 전자 농도는 감소하여 87.8%의 높은 투과율과 <50 ${\Omega}/{\Box}$의 면저항을 갖는 TCO 박막을 합성 하였다.