• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.272-273
• /
• 2006

LTCC(low temperature co-fired ceramics)용 glass/ceramic 복합체를 제조하기 위해 4 종류의 borosilicate계 glass를 선정하고 filler로 $Al_2O_3$ ceramics를 filler 사용하여 30~50 vol% glass frit에 따른 소결 및 유전 특성에 대하여 조사하였다. Glass frit은 $SiO_2$와 $B_2O_3$ 함량비를 고정한 후 R(CaO, BaO, ZnO, $Bi_2O_3$)에 따라 유리 연화온도(Ts)와 함량이 소결에 미치는 영향 및 유전 특성 변화를 고찰한 결과, CaO-$B_2O_3-SiO_2$ glass의 경우 다량의 2 차상이 형성되었고, 이에 $900^{\circ}C$ 이하에서 완전 소결이 이루어지지 않았으며, BaO-$B_2O_3-SiO_2$ glass는 celsian($BaAl_2Si_2O_8$) 결정이 형성되면서 소결성의 저하를 갖고 왔으며, ZnO-$B_2O_3-SiO_2$ glass는 소결이 진행됨에 따라 주상이 $Al_2O_3$에서 gahnite($ZnAl_2O_4$) 결정이 형성되면서 품질계수가 크게 증가하였으며, $Bi_2O_3-B_2O_3-SiO_2$ glass는 45 vol%일 때 $900^{\circ}C$에서부터 일정한 선수축율 특성을 나타내었지만, 다량의 액상으로 인하여 유전 특성의 저하를 나타내었다.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.3C no.4
• /
• pp.140-145
• /
• 2003

The influence of microstructure nonuniformity on the electrical characteristics of ZnO varistors was analyzed with the added amount of $Al_2$O$_3$ dopants. $Al_2$O$_3$ doping can effectively inhibit grain growth. When $Al_2$O$_3$ content is in the range between 0-0.1 %, the average grain size and the standard deviation decrease quickly and the grain growth is strongly inhibited. Therefore, it is possible to increase the microstructure uniformity by accurate addition of $Al_2$O$_3$ to the ZnO varistor. The breakdown voltage increases with the decrease of standard deviation. The greater the uniformity of the Zno varistor means the higher the global breakdown voltage. The $Al_2$O$_3$ dopants having about 0-0.023 wt% content can effectively improve the voltage ratio, and the voltage ratio reaches a minimum value of 2.32 at an $Al_2$O$_3$ content of 0.005 wt%.

• Korean Journal of Materials Research
• /
• v.21 no.1
• /
• pp.67-71
• /
• 2011

La doped CuO-ZnO-$Al_2O_3$ powders are prepared by sol-gel method with aluminum isopropoxide and primary distilled water as precursor and solvent. In this synthesized process, the obtained metal oxides caused the precursor such as copper (II) nitrate hydrate and zinc (II) nitrate hexahydrate were added. To improve the surface areas of La doped CuO-ZnO-$Al_2O_3$ powder, sorbitan (z)-mono-9-octadecenoate (Span 80) was added. The synthesized powder was calcined at various temperatures. The dopant was found to affect the surface area and particle size of the mixed oxide, in conjunction with the calcined temperature. The structural analysis and textual properties of the synthesized powder were measured with an X-ray Diffractometer (XRD), a Field-Emission Scanning Electron Microscope (FE-SEM), Bruner-Emmett-Teller surface analysis (BET), Thermogravimetry-Differential Thermal analysis (TG/DTA), $^{27}Al$ solid state Nuclear Magnetic Resonance (NMR) and transform infrared microspectroscopy (FT-IR). An increase of surface area with Span 80 was observed on La doped CuO-ZnO-$Al_2O_3$ powders from $25m^2$/g to $41m^2$/g.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.4
• /
• pp.422-425
• /
• 2004

In this study, the AZO thin films were prepared as a function of oxygen gas flow ratio at room temperature by FTS(Facing Targets Sputtering) apparatus using Zn:Al(metal)-Zn:Al(metal) or Zn(metal)-ZnO:Al(ceramic). The film thickness, crystalline and electric properties of AZO thin film was evaluated by $\alpha$-step, XRD and 4-point probe. In the results, the resistivity of AZO thin film was shown the lowest value about 8${\times}$10$^{-2}$ $\Omega$-cm(Zn:Al-Zn:Al), 3${\times}$10$^{-1}$ $\Omega$-cm(Zn-ZnO:Al) at the oxygen gas flow ratio 0.3. And the AZO thin film has good crystalline at oxygen gas flow ration 0.4, using Zn:Al-Zn:Al targets.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1273-1276
• /
• 2007

We provide a newly developed dry etching process for the fabrication of ZnO-based oxide TFTs. The etching characteristics of ZnO (active layer) and $Al_2O_3$ (gate insulator) thin films were systematically investigated when the etching gas mixtures and their mixing ratios were varied in the heliconplasma etching system.

• Journal of the Korean Ceramic Society
• /
• v.42 no.2 s.273
• /
• pp.110-116
• /
• 2005

Suitable compositions which are sinterable at low temperature in the $BaO-B_{2}O_{3}-ZnO$ glass system were investigated as a function of the ratio between BaO and ZnO. The effect of $Al_{2}O_3$ filler on densification and physical characteristics of the glass was also examined. When the amount of $Al_{2}O_3$ filler increased, the densification rate and the values of dielectric constant, thermal expansion coefficient and hardness in the glass-filler composites decreased gradually. The decreasing rate of the physical properties accelerated when fine $Al_{2}O_3$ filler was used. However, the fracture toughness of the composite rather increased due to the existence of filler particles and pores which effectively suppressed crack propagation with addition of fine $Al_{2}O_3$ filler.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1994.05a
• /
• pp.79-79
• /
• 1994

• Journal of the Korean Vacuum Society
• /
• v.22 no.3
• /
• pp.119-125
• /
• 2013

In this study, we studied the properties of ZnO(Al) and ZnO(AlGa) thin film according to film thickness deposited on SLG by In-line magnetron sputtering system. XRD, FESEM, 4-point probe, Hall measurement system and UV/Vis-NIR spectrophotometer were employed to analyze the properties of ZnO(Al) and ZnO(AlGa) thin film. The all films exhibited (002) preferential orientation with clear peak shape and high intensity. The carrier concentration and Hall mobility of ZnO(Al) and ZnO(AlGa) thin film were improved with increasing thickness. The resistivity of both films decreased when the film thickness was raised from 500 nm to 1,450 nm. And then relatively the resistivity of ZnO(AlGa) film was lower than that of ZnO(Al) film. The transmittance of the films decreased with increasing film thickness but all films exhibited optical transmittances of over 83.3% in the visible region.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.10
• /
• pp.923-929
• /
• 2006

Single crystalline ZnO films were successfully grown on R-plane sapphire substrates by plasma-assisted molecular beam epitaxy. Epitaxial relationship between the ZnO film and the R-plane sapphire was determined to be $[-1101]Al_2O_3{\parallel}[0001]ZnO,\;[11-20]Al_2O_2{\parallel}[-1100]ZnO$ based on the in-situ reflection high-energy electron diffraction analysis and confirmed again by high-resolution X-ray diffraction measurements. Grown (11-20) ZnO films surface showed mound-like morphology along the <0001>ZnO direction and the RMS roughness was about 4 nm for $2{\mu}m{\times}2{\mu}m$ area.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1279-1280
• /
• 2007

$Al_{2}O_{3}$ 절연막을 전하포획층으로 이용하여 Top 게이트 ZnO 나노선 전계효과트랜지스터를 제작하였고, 메모리 효과를 관찰하였다. $Al_{2}O_{3}$ 층을 게이트 절연막과 전하포획층으로 사용하였다. 대표적인 Top 게이트 ZnO 나노선 전계효과트랜지스터에 대하여 게이트 전압을 Double sweep 하였을 때의 드레인 전류-게이트 전압 특성이 반시계 방향의 히스테리시스와 문턱전압변화를 나타냈다. 펄스 형태의 게이트 전압을 1초 동안 인가한 후에, 드레인 전류-게이트 전압 특성의 문턱전압 변화가 0.3 V에서 0.8 V로 증가하였다. 이러한 특성은 게이트 전극에서 음전하 캐리어가 음의 게이트 전압에 대하여 $Al_{2}O_{3}$ 층에 충전되고, 양의 게이트 전압에 대하여 방전되는 것을 나타낸다.