• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.596-600
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• 2012

ZnO-$SnO_2$ films were deposited by rf magnetron sputtering using a ZnO-$SnO_2$ (2:1 molar ratio) target. The target was made from a mixture of ZnO and $SnO_2$ powders calcined at $800^{\circ}C$. The working pressure was 1 mTorr, and the rf power was 120 W. The ratio of oxygen to argon ($O_2$:Ar) was varied from 0% to 10%, and the substrate temperature was varied from $27^{\circ}C$ to $300^{\circ}C$. The crystallographic properties and the surface morphologies of the films were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force spectroscopy (AFM). The ZnO-$SnO_2$ films deposited in $O_2$:Ar = 10% exhibited resistivity higher than $10^6{\Omega}cm$ and transmittance of more than 80% in the visible range.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.6
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• pp.350-355
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• 2014

Bottom-gate tin oxide ($SnO_2$) thin film transistors (TFTs) were fabricated on $N^+$ Si wafers used as gate electrodes. 60-nm-thick $SnO_2$ thin films acting as active layers were sputtered on $SiO_2/Al_2O_3$ films. The $SiO_2/Al_2O_3$ films deposited on the Si wafers were employed for gate dielectrics. In order to increase the resistivity of the $SnO_2$ thin films, oxygen mixed with argon was introduced into the chamber during the sputtering. The mobility of $SnO_2$ TFTs was measured as a function of the flow ratio of oxygen to argon ($O_2/Ar$). The mobility variation with $O_2/Ar$ was analyzed through studies on crystallinity, oxygen binding state, optical properties. X-ray diffraction (XRD) and XPS (X-ray photoelectron spectroscopy) were carried out to observe the crystallinity and oxygen binding state of $SnO_2$ films. The mobility decreased with increasing $O_2/Ar$. It was found that the decrease of the mobility is mainly due to the decrease in the polarizability of $SnO_2$ films.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.703-708
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• 2009

In this paper, synthesis here Mn add to Ar any a vacuum an atomosphere $ZnGa_2O_4$ : Mn, ZnO and $Ga_2O_3$ power of 1:1 mole ratio mixture. Manufacture a close examination of oxygen a component variation luminescence a specific character reach an in fluence of $ZnGa_2O_4$ : Mn, luminescence spectrum, the surface a picture and a component ratio measurement, also an explanation of Mn site symmetry and at luminescence spectrum reach an influence from low temperature photoluminescence spectrum.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.45-46
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• 2005

The piezoelectric ZnO thin films were deposited onto Al/Si substrate in order to figure out the crystalline and the residual stress of deposited films. As the $Ar/O_2$ gas ratio is increased, c-axis orientation of deposited films is significantly enhanced and also the residual stresses of ZnO films are all compressive. They are decreased from -1.2 GPa to -950 MPa as the $Ar/O_2$ gas ratio is increased. A diaphragm-based piezoelectric microspeaker fabricated on ONO films shows about 14 mPa output pressure at 1 kHz with $8V_{peak-to-peak}$.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.4
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• pp.483-491
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• 2017

The interdigitated germanium (Ge) meta-lsemiconductor-metal (MSM) photodetectors (PDs) with and without an $SiO_2$ anti-reflection (AR) layer was fabricated, and the effect of $SiO_2$ AR layer on their optoelectronic response properties were investigated in detail. The lowest reflectance of 15.6% at the wavelength of 1550 nm was obtained with a $SiO_2$ AR layer with a thickness of 260 nm, which was in a good agreement with theoretically calculated film thickness for minimizing the reflection of Ge surface. The Ge MSM PD with 260 nm-thick $SiO_2$ AR layer exhibited enhanced device performance with the maximum values of responsivity of 0.65 A/W, the quantum efficiency of 52.2%, and the detectivity of $2.49{\times}10^9cm\;Hz^{0.5}W^{-1}$ under the light illumination with a wavelength of 1550 nm. Moreover, time-dependent switching analysis of Ge MSM PD with 260 nm- thick $SiO_2$ AR layer showed highest on/off ratio with excellent stability and reproducibility. All this investigation implies that 260 nm-thick $SiO_2$ AR layer, which is effective in the reduction in the reflection of Ge surface, has a great potential for Ge based optoelectronic devices.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.867-869
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• 1999

In this study, $SrBi_{2}Ta_{2}O_{9}$(SBT) thin films were etched as a function of $SF_6$/Ar gas mixing ratio in magnetically enhanced inductively coupled plasma(MEICP) system fer a fixed rf power, dc-bias voltage, and chamber pressure. The etch rate of SBT thin film was $1500{\AA}/min$ and the selectivities of photoresist (PR) and $SiO_2$ to SBT thin film were 0.48 and 0.62, respectively when the samples were etched at a rf power of 600W, a dc-bias voltage of -150V, a chamber pressure of 10 mTorr and a gas mixing ratio of $SF_6/(SF_6+A)$=0.1. In order to examine the chemical reactions on the etched surface, X-ray photoelectron spectroscopy(XPS) and secondary ion mass spectrometry(SIMS) were done.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.671-676
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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 at various deposition conditions. We investigated the effect of deposition condition on the surface morphology and dielectric properties of SBN thin films. The optimum of the rougness showed about 4.33 nm in 70/30 of Ar/$O_2$ ratio. The crystallinity and rougness of SBN thin films were increased with the increase of rf power. Also, Deposition rate of SBN thin films was about 4.17 nm/min in 70 W of rf power. The capacitance of SBN thin films were increased with the increase of Ar/$O_2$ ratio, rf power and deposition temperature respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.6
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• pp.449-453
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• 2003

Ferroelectric YMnO$_3$ thin films were etched with Ar/Cl$_2$ and CF$_4$/Cl$_2$ inductively coupled plasma (ICP). The maximum etch rate of YMnO$_3$ thin film was 300 $\AA$/min at a Ar/Cl$_2$ gas mixing ratio of 2/8, a RF power of 800 W, a DE bias of 200 V, a chamber pressure of 15 mTorr, and a substrate temperature of 30 $^{\circ}C$. From the X-ray photoelectron spectroscopy (XPS) analysis, yttrium etched by chemical reactions with Cl radicals assisted by Ar ion bombardments in Ar/Cl$_2$ plasma. In CF$_4$/Cl$_2$ plasma, yttrium are remained on the etched surface of YMnO$_3$ and formed of nonvolatile YF$_{x}$ compounds manganese etched effectively by chemical reactions with Cl and F radicals. 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 value than that in CF$_4$/Cl$_2$ plasma. It indicates that the crystallinty of YMnO$_3$ thin film is more easily damaged by the Ar ion bombardment than the changes of stoichiometry due to nonvolatile etch by-products.s.

• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.74-77
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• 2017

In this work, we investigated the etching characteristics of TaNO thin films and the selectivity of TaNO to $SiO_2$ in an $O_2$/CF4/Ar inductively coupled plasma (ICP) system. The maximum etch rate of TaNO thin film was 297.1 nm/min at a gas mixing ratio of O2/CF4/Ar (6:16:4 sccm). At the same time, the etch rate was measured as a function of the etching parameters, such as the RF power, DC-bias voltage, and process pressure. X-ray photoelectron spectroscopy analysis showed the efficient destruction of the oxide bonds by the ion bombardment, as well as the accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the $CF_4$-containing plasmas.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.100-100
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• 2000

Aluminium oxide (Al2O3) films have been investigated for many applications such as insulating materials, hard coatings, and diffusion barriers due to their attractive electrical and mechanical properties. In recent years, application of Al2O3 films for dielectric materials in integrated circuits as gates and capacitors has attracted much attention. Various deposition techniques such as sol-gel, metalorganic decomposition (MOD), sputtering, evaporation, metalorganic chemical vapor deposition (MOCVD), and pulsed laser ablation have been used to fabricate Al2O3 thin films. Among these techniques, reactive sputtering has been widely used due to its high deposition rate and easy control of film composition. It has been also reported that the sputtered Al2O3 films exhibit superior chemical stability and mechanical strength compared to the films fabricated by other processes. In this study, Al2O3 thin films were deposited on Pt/Ti/SiO/Si2 and Si substrates by DC reactive sputtering at room temperature with variation of the Ar/O2 ratio in sputtering ambient. Crystalline phase of the reactively sputtered films was characterized using X-ray diffractometry and the surface morphology of the films was observed with Scanning election microscopy. Effects of Th Ar/O2 ratio characteristics of Al2O3 films were investigated with emphasis on the thickness dependence of the dielectric properties. Correlation between the dielectric properties and the microstructure was also studied