• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 추계학술대회 논문집
• /
• pp.96-96
• /
• 2007

Low voltage organic TFTs (OTFTs) and ZnO based TFTs (<5V), utilizing room temperature deposited $Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7$ (BZN) thin films were recently reported, pointing to high-k gate insulators as a promising route for realizing low voltage operating flexible electronics. $Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7$ (BZN) thin film is one of the most promising materials for gate insulator because of its large dielectric constant (~60) at room temperature. However their tendency to suffer from relatively high leakage current at low electric field (>0.3MV/cm) hinder the application of BZN thin films for gate insulator. In order to improve leakage current characteristics of BZN thin film, we mixed 30mol% MgO with 70mol% BZN and their dielectric and electric properties were characterized. We fabricated field-effect transistors with transparent oxide semiconductor ZnO serving as the electron channel and high-k $(Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7)_{0.7}(MgO)_{0.3}$ as the gate insulator. The devices exhibited low operation voltages (<4V) due to high capacitance of the $(Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7)_{0.7}(MgO)_{0.3}$ dielectric.

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

• 반도체디스플레이기술학회지
• /
• 제7권2호
• /
• pp.63-67
• /
• 2008

The MgO protective layer plays an important role in plasma display panels (PDPs). Our previous work demonstrated that the properties of MgO thin film could be improved, which were deposited by ion beam assisted deposition (IBAD). However arc discharge always occurs during the IBAD process. To avoid this problem, oxygen neutral beam assisted deposition (NBAD) is used to deposit MgO thin films in this paper. The energy of the oxygen neutral beam was used as the parameter to control the deposition. The experimental results showed that the oxygen neutral beam energy was effective in determining in F/$F^+$ centers, crystal orientation, surface morphology of the MgO thin film, and the discharge characteristics of AC PDP. The lowest firing voltage $(V_f)$ and the highest secondary electron emission coefficient $(\gamma)$ were obtained when the neutral beam energy was 300 eV.

• 한국진공학회지
• /
• 제16권5호
• /
• pp.338-342
• /
• 2007

MgO는 플라즈마 디스플레이 패널 (Plasma Display Panel, PDP)의 보호막으로 널리 쓰이고 있다. 본 실험에서는 산소 이온 빔을 이용하여 증착된 MgO 보호막의 특성을 조사하였다. MgO 증착 시 보조 산소 이온 빔의 에너지를 변화시킴에 따라 MgO 보호막의 특성과 PDP 패널 발광특성에 미치는 영향을 분석하였다. 본 연구에서는 산소 이온 에너지가 300 eV 일 때 소자의 방전개시전압이 가장 낮게 나타났고, 발광 휘도 및 발광 효율은 가장 높게 나타났다. 또한 산소 이온 빔의 조사에너지에 따라 MgO 박막의 결정성 및 표면조도가 크게 영향을 받는 것을 확인할 수 있었다. 산소 이온 빔 보조 증착 방법을 이용하여 패널의 발광 휘도와 발광 효율 등 발광특성을 개선하였다.

• Progress in Superconductivity
• /
• 제3권2호
• /
• pp.188-192
• /
• 2002

To introduce flux pinning center in HTS-BSCCO system, nano-size MgO particles were uniformly distributed within the Bi-2223 grain by partial hydration of MgO. The existing method MgO doped Bi-2223 used nato-size MgO powders, which resulted in agglomeration during mixing or grain growth during heat-treatment due to the high surface energy of the fine particles. By hydration of the MgO surface, the agglomeration of the MgO powders was avoided and the size of remaining MgO core was controlled by changing hydration medium and time. The thin film obtained by spin coating of (Bi_$1.8/Pb_{0.4}$)$Sr_2$$_{Ca}$$2.2/Cu_3$ $O_{y}$ nitrate solution mixed with hydrated MgO showed the even distribution of nano-size MgO particles in the Bi-2212 grains.s.s.

• 한국세라믹학회지
• /
• 제43권1호
• /
• pp.62-67
• /
• 2006

Time-of-flight impact-collision ion scattering spectroscopy (TOF-ICISS) using 2 keV $He^+$ ion was applied to study the geometrical structure of the $BaTiO_3$ thin film which was grown on the MgO(100) surface. Hetero-epitaxial $BaTiO_3$ layers were formed on the MgO(100) surface by thermal evaporation of titanium followed first by oxidation at $400^{\circ}C$, subsequently by barium evaporation, and finally by annealing at $800^{\circ}C$. The atomic structure of $BaTiO_3$ layers was investigated by the scattering intensity variation of $He^+$ ions on TOF-ICISS and by the patterns of reflection high energy electron diffraction. The scattered ion intensity was measured along the <001> and <011> azimuth varying the incident angle. Our investigation revealed that perovskite structured $BaTiO_3$ layers were grown with a larger lattice parameter than that of the bulk phase on the MgO(100) surface.

• 한국세라믹학회지
• /
• 제32권3호
• /
• pp.305-312
• /
• 1995

Thin films of Pb(Mg, Zn)1/3Nb2/3O3 were fabricated by spin coating the Pb-Mg-Zn-Nb-O complex alkoxide sols on(111) Pt-coated MgO (100) planes. It was observed that the content of H2O and the rheological characteristics of sol greatly influenced the orientation of perovskite grains after thin-film formation. A strong preferential orientation of (100)-type planes of the perovskite grains was obtained for the sol aged for 15 days with the molar ratio of H2O to total metal alkoxides=2. As small angle X-ray scattering experiment in the Porod region was performed to correlate the observed preferential orientation with the network structure of precursors at various stage of aging. It was shown that the degree of branching of the Pb-Mg-Zn-Nb-O precursor chain had a direct effect on the preferred oreintation, and weakly branched precursor systems led to highly oriented grains after thin-film formation.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
• /
• pp.768-771
• /
• 2004

Pb0.5,Sr0.5TiO3(PST) thin films were deposited on Si with MgO (100) buffer layer by the alkoxide-based sol-gel method. Structural and dielectric properties of PST thin films for the tunable microwave device applications were investigated. For the MgO/Si buffer layer, the PST thin films exhibited highly (100) orientation. The MgO buffer layer affects the stress state of the (100)-oriented PST thin films. The dielectric constant, tunability, and FOM of the highly (100)-oriented PST thin film increased with increasing annealing temperature due to the decrease in lattice distortion. The differences in dielectric properties may be attributed to the change in the film stress. The dielectric constants, dielectric loss and tunability of the PST thin films deposited on the MgO/Si substrates measured at 10 kHz were 822, 0.025, and 80.1%, respectively.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제52권10호
• /
• pp.447-450
• /
• 2003

This paper presents a process optimization of antireflection (AR) coating on crystalline Si solar cells. Theoretical and experimental investigations were performed on a double-layer AR (DLAR) coating of MgF$_2$/CeO$_2$. We investigated CeO$_2$ films as an AR layer because they have a proper refractive index of 2.46 and demonstrate the same lattice constant as Si substrate. RF sputter grown CeO$_2$ film showed strong dependence on a deposition temperature. The CeO$_2$ deposited at 40$0^{\circ}C$ exhibited a strong (111) preferred orientation and the lowest surface roughness of 6.87 $\AA$. Refractive index of MgF$_2$ film was measured as 1.386 for the most of growth temperature. An optimized DLAR coating showed a reflectance as low as 2.04% in the wavelengths ranged from 0.4${\mu}{\textrm}{m}$ to 1.1${\mu}{\textrm}{m}$. We achieved the efficiencies of solar cells greater than 15% with 3.12% improvement with DLAR coatings. Further details on MgF$_2$, CeO$_2$ films, and cell fabrication parameters are presented in this paper.

• 한국재료학회지
• /
• 제8권8호
• /
• pp.667-671
• /
• 1998

이 연구에서는 HVPE법으로 $MgAl_{2}O_{4}$ 기판 위에 GaN를 서로 다른 조건에서 성장시키고, 성장된 GaN의 PL특성을 조사하였다. $MgAl_{2}O_{4}$ 기판위에 성장된 GaN는 $MgAl_{2}O_{4}$ 기판으로부터 Mg의 out-diffusion에 의한 auto-doping 효과에 의하여 불순물이 첨가된 GaN의 PL 성질을 나타내었다. Mg과 관련된 발광 강도는 GaN의 성장온도가 증가함에 따라 GaN의 표면에서 Mg의 재증발에 의하여 감소하였으며, GaN의 두께에 대하여 지수 함수적으로 감소하였다. 두 개의 무한 고체 사이에서 농도 차에 의한 확산현상을 고려하여 구한 GaN 내에서 Mg 원자의 확산계수는 D= 2$\times$$lO^{-10}\textrm{cm}^2/sec. 이었다.