• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.569-570
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• 2006

Effects of the evaporation rate of MgO films using electron beam were investigated on the MgO properties and the discharge characteristics of the plasma display panel (PDP). The evaporation rate was changed from $3{\AA}$/sec to $15{\AA}$/sec at a substrate temperature of $300^{\circ}C$. MgO properties such as crystal orientation, surface roughness, contact angle, and film structure were inspected using XPS, AFM, drop shape analysis and SEM. We also studied the relation between MgO properties and PDP discharging characteristics. The minimum firing voltage and maximum efficacy were obtained at evaporation rate of $5{\AA}$/sec. In the MgO film deposited at $5{\AA}$/sec, (200) orientation was most intensive and surface roughness was minimum.

• 한국전기전자재료학회논문지
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• 제16권9호
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• pp.812-815
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• 2003

In this study, the MgO thin-film passivation layer was adopted to protect passive matrix organic light emitting diode(PMOLED) with the cathode separator from moisture and oxygen. Using the substrate rotate and tilt technique during the deposition, the organic and cathode layers were perfectly covered with MgO. And then, we analyzed the difference of the current-voltage and luminescence characteristics between passivated OLED of the MgO and non-passivated OLED. It was found that the number of dark spot generated from the degradated pixel was decreased owing to the Mgo thin-film passivation layer using the tilt ＆ rotate technique. And the half-life time passivated OLED was improved two times more. Thus, the MgO could be vaccum-deposited under the low temperature and had a merit that the organic layer was not much affected. We can consider that MgO thin film passivation method can be adopted to protect the OLED from moisture and oxygen and can offer the enhancement of lifetime.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.355-355
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• 2010

The epitaxial growth of MgO film on Fe(001) has been investigated by scanning tunneling microscopy (STM). After confirming the clean Fe(001)-c($2{\times}2$) substrate by STM, Mg was deposited at room temperature (RT) under $O_2$ partial pressure of $10^{-7}\;Torr$. The MgO was grown as clusters, not as an epilayer even after postannealing at $400^{\circ}C$, as shown in Figure (a). On the contrary, when Mg was deposited on Fe(001)-c($2{\times}2$) at RT and post-oxidized through exposing $O_2$ at partial pressure $10^{-7}\;Torr$, the thin-layered film with some clusters was formed. Extended-annealing at $400^{\circ}C$ reduced the cluster density, and finally the single and epitaxial MgO-c($2{\times}2$) film was formed on Fe(001)-c($2{\times}2$) as shown in Figure (b). This ultrathin MgO film formed on Fe is expected to be applied to many technological applications, such as catalysis, microelectronics, and magnetic devices.

• 한국재료학회지
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• 제16권11호
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• pp.715-718
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• 2006

Porous hydroxyapatite (HAp) scaffolds have been prepared by using the slurry including HAp and magnesia based on the replication of polymer sponge substrate. The influence of MgO content in slurry on the pore morphology and size, density, porosity, and mechanical strength of porous HAp scaffolds was investigated. The obtained scaffolds with average pore sizes ranging 150 to 300 mm had open, relatively uniform, and interconnected porous structure regardless of MgO content. As the MgO content increased, the pore network frame of scaffolds became to be relatively stronger, even though the pore size was not much changed. The compressive strength of the scaffolds increased rapidly with the increase of MgO content because of increasing the pore wall thickness and density of the scaffolds. As a result, the porosity, density, and compressive strength of the porous HAp scaffolds prepared by the sponge method were significantly affected by the addition of MgO.

• 한국재료학회지
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• 제10권2호
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• pp.160-165
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• 2000

Sputter Cu(1-4.5at.%Mg) alloy를 100mTorr이하의 산소압력에서 온도를 증가시키며 열처리하였을 때 표연과 계면에서 형성된 MgO의 확산방지막 특성을 살펴보았다 먼저, $Cu(Mg)/SiO_2/Si$ 구조의 샘플을 열처리했을 때 계면에서는 $2Mg+SiO_2{\rightarrow}2MgO+Si$의 화학반응에 의해 MgO가 형성되는데 이 MgO충에 의해 Cu가 $SiO_2$로 확산되는 것이 현저하게 감소하였다. TiN/Si 기판 위에서도 Cu(Mg)과 TiN 계면에 MgO가 형성되어 Cu(4.5at.%Mg)의 경우 $800^{\circ}C$까지 Cu와 Si의 확산을 방지할 수 있었다. 표면에 형성된 MgO위에 Si을 증착하여 $Si/MgO(150\;{\AA})/Cu(Mg)/SiO_2/Si$구조로 만든 후 열처리했을 때 $150\;{\AA}$의 MgO는 $700^{\circ}C$까지 Si과 Cu의 확산을 방지할 수 있었다. 표면에 형성된 MgO($150\;{\AA}$)의 누설전류특성은 break down 5V, 누설전류 $10^{-7}A/\textrm{cm}^2$의 값을 나타냈다. 또한 $Si_3N_4/MgO$ 이중구조에서는 매우 낮은 누설전류밀도를 나타냈으며 MgO에 의해 $Si_3N_4$ 증착시 안정적인 계면이 형성됨을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1806-1808
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• 1999

The electrical and physical characteristics of MgO and Pt thin-films on Si substrate, deposited by r.f magnetron sputtering. It were analyzed with annealing condition($1000^{\circ}C$ for 120 min) by four point probe, a-step, SEM and XRD. Until $1000^{\circ}C$ of annealing temperature, MgO medium layer had the properties of improving Pt adhesion to $SiO_2$ and insulation without chemical reaction to Pt thin-films and the resistivity of Pt thin-films was improved. In the analysis of properties of Pt-RTD, TCR value had $3927ppm/^{\circ}C$ and liner in the temperature range of room temperature ${\sim}400^{\circ}C$.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.770-775
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• 2004

Although $High-T_c $superconducting HTS antennas have high efficiency and high gain, narrow bandwidth due to the high Q is the major limitation for application of satellite communication and mobile communication. Defining bandwidth as the frequency range over which standing wave ratio (SWR) is 2:1 or less, HTS antenna bandwidths are typically less than 1 %. Thus considerable effort has been focused on developing HTS antennas for broadband operation. In this work the HTS antenna array, using the bipin antenna which consisted of two triangle-radiation patches, was designed and fabricated using a ${YBa}_2{Cu}_3{O}_7x (YBCO)$ superconducting thin film on a MgO substrate for broadband operation. Also gold antennas with the same dimension as our HTS antennas were fabricated on the MgO substrate for the comparison. Experimental results for both antennas were reported in terms of radiation patterns, return losses, bandwidths and other various characteristics. The center frequency of HTS antennas was 20.28 GHz and the bandwidth obtained was significant 10 %.

• Metals and materials international
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• 제24권6호
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• pp.1241-1248
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• 2018

The reactive wetting behaviors of molten Zn-Al-Mg alloys on MnO- and amorphous (a-) $SiO_2$-covered steel sheets were investigated by the sessile drop method, as a function of the Al and Mg contents in the alloys. The sessile drop tests were carried out at $460^{\circ}C$ and the variation in the contact angles (${\theta}_c$) of alloys containing 0.2-2.5 wt% Al and 0-3.0 wt% Mg was monitored for 20 s. For all the alloys, the MnO-covered steel substrate exhibited reactive wetting whereas the $a-SiO_2$-covered steel exhibited nonreactive, nonwetting (${\theta}_c>90^{\circ}$) behavior. The MnO layer was rapidly removed by Al and Mg contained in the alloys. The wetting of the MnO-covered steel sheet significantly improved upon increasing the Mg content but decreased upon increasing the Al content, indicating that the surface tension of the alloy droplet is the main factor controlling its wettability. Although the reactions of Al and Mg in molten alloys with the $a-SiO_2$ layer were found to be sluggish, the wettability of Zn-Al-Mg alloys on the $a-SiO_2$ layer improved upon increasing the Al and Mg contents. These results suggest that the wetting of advanced high-strength steel sheets, the surface oxide layer of which consists of a mixture of MnO and $SiO_2$, with Zn-Al-Mg alloys could be most effectively improved by increasing the Mg content of the alloys.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.129-132
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• 2003

Yttria stabilized zirconia (YSZ) buffer layers were deposited by a metal organic chemical vapor deposition (MOCVD) technique using single liquid source for the application of YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) coated conductor. Y:Zr mole ratio was 0.2:0.8, and tetrahydrofuran (THF) was used as a solvent. The (100) single crystal MgO substrate was used for searching deposition condition. Bi-axially oriented CeO$_2$ and NiO films were fabricated on {100}〈001〉 Ni substrate by the same method and used as templates. At a constant working pressure of 10 Torr, the deposition temperatures (660~80$0^{\circ}C$) and oxygen flow rates (100~500 sccm) were changed to find the optimum deposition condition. The best (100) oriented YSZ film on MgO was obtained at 74$0^{\circ}C$ and $O_2$ flow rate of 300 sccm. For YSZ buffer layer with this deposition condition on CeO$_2$/Ni template, full width half maximum (FWHM) values of the in-plane and out-of-plane alignments were 10.6$^{\circ}$ and 9.8$^{\circ}$, respectively. The SEM image of YSZ film on CeO$_2$/Ni showed surface morphologies without microcrack.k.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.734-737
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• 2004

The metal-ferroelectric-semiconductor (MFS) structure is widely studied for nondestructive readout (NDRO) memory devices, but conventional MFS structure has a critical problem. It is difficult to obtain ferroelectric films like PZT on Si substrate without interdiffusion of impurities such as Pb, Ti and other elements. In order to solve these problems, the metal-ferroelectric-insulator-semiconductor (MFIS) structure has been proposed with a buffer layer of high dielectric constant such as MgO, $Y_2O_3$, and $CeO_2$. In this study, the etching characteristics (etch rate, selectivity) of MgO thin films were etched using $Cl_2/Ar$ plasma. The maximum etch rate of 85 nm/min for MgO thin films was obtained at $Cl_2$(30%)/Ar(70%) gas mixing ratio. Also, the etch rate was measured by varying the etching parameters such as ICP rf power, dc-bias voltage, and chamber pressure. Plasma diagnostics was performed by Langmuir probe (LP) and optical emission spectroscopy (OES).