• 반도체디스플레이기술학회지
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• 제8권3호
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• pp.57-60
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• 2009

Transparent electrode ZnO:Al(AZO)films were deposited on a PES (polyethersulfone) polymer substrate for thin film solar cells applications. A PES substrate with a thickness of 0.2mm and transmittance > 90% in the visible range was used because it is light weight and can deform easily. AZO thin films were prepared at a fixed DC power, $PO_2\;=\;P(O_2)/[P(O_2)\;+\;P(Ar)]$, and various substrate temperatures. The properties of AZO thin films were examined by X-ray diffraction, UV/VIS spectroscopy, four-point probe, Hall measurements, and field emission scanning electron microscopy. The lowest resistivity of all the films was $4.493\;{\times}\;10^{-4}\;[\Omega-cm]$ and the transmittance was > 80% in the visible range.

• 한국전기전자재료학회논문지
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• 제29권5호
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• pp.279-283
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• 2016

In this study, we intended to achieve both antibacterial properties and electromagnetic shielding using the Al-doped ZnO (AZO) films. FTS (Facial Target Sputtering) magnetron sputtering was used for the AZO thin films instead of the conventional RF sputtering because the FTS sputtering could avoid the damage for the plasma as well as fabrication of thin films with a high quality. The 300-nm thick AZO thin films grown on glass substrate showed a resistivity of about $7{\times}10^{-4}{\Omega}-cm$ and a transmittance of about 90% at a wavelength of 550 nm. AZO thin films were investigated for the electromagnetic shielding effectiveness measured by 2-port network method at 1.5 ~ 3 GHz. The AZO (300 nm)/glass films showed an EMI shielding effectiveness of approximately 27 dB. An antibacterial effect was measured by the film attachment method (JIS Z 2801). The percent reductions of bacteria by AZO films were 99.99668% and 99.99999% against Staphylococcus aureus and Escherichia coli, respectively.

• 한국진공학회지
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• 제20권2호
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• pp.141-145
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• 2011

ZnO:Al 박막을 RF magnetron sputtering 법을 이용하여 초기 압력에 따라 증착하고 박막의 구조적, 광학적, 전기적 특성을 연구하였다. 초기 압력 변화에 의해 ZnO:Al 박막의 특성의 변화를 확인하였고 고품질의 박막을 얻을 수 있었다. 모든 ZnO:Al 박막에서 (002)면의 우선 배향성을 보였으며 가시광선 영역(400~800 nm)에서 85% 이상의 좋은 투과도를 보였다. 초기 압력이 낮아질수록 결정성, 비저항 그리고 성능지수 특성이 향상됨을 확인하였다. 초기 압력에 따른 비저항의 향상은 결정립 크기 변화에 의한 것으로 판단된다.

• 한국재료학회지
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• 제14권5호
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• pp.328-333
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• 2004

Transparent ZnO:Al conductor films for the optoelectronic devices were deposited by using the capacitively coupled DC magnetron sputtering method. The effect of Al doping concentration and discharge power on the electrical and optical properties of the films was studied. The film resistivity of $8.5${\times}$10^{-4}$ $\Omega$-cm was obtained at the discharge power of 40 W with the ZnO target doped with 2 wt% $Al_2$$_O3$. The transmittance of the 840 nm thick film was 91.7% in the visible waves. Increasing doping concentration of 3 wt% $Al_2$$O_3$ in ZnO target results in significant decrease of film resistivity, which may be due to the formation of $Al_2$$O_3$ particles in the as-deposited ZnO:Al film and the reduced ZnO grain sizes. Increasing DC power from 40 to 60 W increases deposition rate by more than 50%, but can induce high defect density in the film, resulting in higher film resistivity.

• 센서학회지
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• 제33권5호
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• pp.353-358
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• 2024

Al-Ni thin films were fabricated using combinatorial sputtering system to realize highly sensitive surface acoustic wave (SAW) devices. The Al-Ni sample library was grown with various chemical compositions and electrical resistivities, which provided important information for selecting the most suitable materials for SAW devices. As acoustic waves generated from piezoelectric materials are significantly affected by the resistivity and density of the interdigital transducer (IDT) electrodes, three types of Al-Ni thin films with different Al contents were fabricated. The thickness of the Al-Ni thin film used in the SAW-IDT electrode was fixed at 100 nm. As the Al content of the Al-Ni film decreased from 79.2 to 24.5 at%, the resistivity increased slightly from 4.8 to 5.8 × 10^-5 Ω-cm, whereas the calculated density increased significantly from 3.6 to 6.9 g/cm³. The SAW device composed of Al-Ni IDT electrodes resonated at 71 MHz without frequency shifts; however, the selectivity of the resonant frequency and insertion loss deteriorated as the Al content decreased. When there is no significant difference in the electrical characteristics of the SAW-IDT electrodes, the performance of the SAW devices can be determined by the density of the IDT electrodes.

• 센서학회지
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• 제11권1호
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• pp.18-27
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• 2002

스크린 프린팅법으로 $Al_2O_3$ 기판 위에 $LaFeO_3$를 기본물질로 하여 $Al_2O_3$를 각각 2Wt.%, 5wt.%, 10wt.%를 첨가한 후막을 제조하였다. 열처리 온도에 따른 후막의 구조적, 전기적 특성과 암모니아 가스에 대한 감지특성을 조사하였다. X선 회절에서, 첨가한 $Al_2O_3$는 $1200^{\circ}C$까지의 열처리에도 $LaFeO_3$와 반응하여 화합물을 형성하지 않음을 확인하였다. 전자현미경 사진에서 $Al_2O_3$의 첨가량에 따른 열처리에 대한 입자의 변화는 차이를 보이지 않았다. 후만의 전기적 특성에서 활성화 에너지가 높고 전기저항이 작은 시료에서 가스감도가 좋았다. $Al_2O_3$를 2wt.% 첨가하여 $1200^{\circ}C$에서 열처리한 후막은 100ppm $NH_3$ 가스에 대해 동작온도 $350^{\circ}C$에서 210%의 감도를 보였다. 이 후막은 $NH_3$ 가스에 대해 우수한 선택성을 보였다.

• Transactions on Electrical and Electronic Materials
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• 제11권2호
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• pp.81-84
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• 2010

Al-doped ZnO (AZO) films were prepared by an Ar:$H_2$ gas radio frequency (RF) magnetron sputtering system with a AZO ($2\;wt{\cdot}%\;Al_2O_3$) ceramic target at the low temperature of $100^{\circ}C$ and annealed in hydrogen ambient at the temperature of $300^{\circ}C$. To investigate the influence of the $H_2$ flow ratio on the properties of the AZO films, the $H_2$ flow ratio was changed from 0.5% to 2%. As a result, the AZO films, deposited with a 1% $H_2$ addition, showed a resistivity of $11.7\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$. When the AZO films were annealed at $300^{\circ}C$ for 1 hour in a hydrogen atmosphere, the resistivity decreased from $11.7\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$ to $5.63\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$. The lowest resistivity of $5.63\;{\times}\;10^{-4}{\Omega}{\cdot}cm$ was obtained by adding 1% hydrogen gas to the deposition and annealing process. The X-ray diffraction patterns of all the films showed a preferable growth orientation in the (002) plane. The spectrophotometer measurements showed that the transmittance of 85% was obtained by the film deposited with the $H_2$ flow ratio of 1% at 940 nm for GaAs/GaAlAs LEDs.

• 한국표면공학회지
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• 제54권1호
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• pp.30-36
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• 2021

In this study, double-layered anodizing films were formed on Al 5052 and Al 6061 alloys consecutively first in sulfuric acid and then in oxalic acid, and hardness, withstand voltage, surface roughness and acid resistance of the anodizing films were compared with single-layered anodizing films in sulfuric acid and oxalic acid electrolytes. Hardness of the double-layered anodizing film decreased with increasing ratio of inner layer to outer layer for both Al 5052 and Al 6061 alloys, suggesting that outer anodizing film formed in sulfuric acid electrolyte is damaged during the second anodizing in oxalic acid electrolyte. Withstand voltage of the double-layered anodizing films increased with increasing the thickness ratio of inner layer to outer layer. Surface roughness of the double-layered anodizing films were comparable with that of single-layered anodizing film formed in sulfuric acid but higher than that of single layer anodizing film formed in oxalic acid electrolyte. In acid resistance test, all of the double-layered and single-layered anodizing films showed good acid resistance more than 3 h without any visible gas evolution, which is attributable to sealing of pores. Based on the experimental results obtained in this work, it is possible to design a double-layered anodizing film with cost-effectiveness and improved physical and electrical properties by combining two consecutive anodizing processes of sulfuric acid anodizing and oxalic acid anodizing methods.

• 센서학회지
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• 제16권3호
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• pp.240-245
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• 2007

AlN thin film for SAW filter application was deposited on (100) silicon, sapphire, $Si_{3}N_{4}$/Si, and $Al_{2}O_{3}$/Si substrates by reactive magnetron sputtering method, respectively. The structural characteristics were dependent on the structure of substrates. Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Atomic Force Microscope (AFM) have been used to analyze structural properties and preferred orientation of AlN thin films. Preferred orientation and SAW characteristic of AlN were improved by insertion of $Al_{2}O_{3}$ buffer layer. Insertion loss of SAW devices using AlN/Si and AlN/$Al_{2}O_{3}$/Si were about 33.27 dB and 30.20 dB, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.207-207
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• 2009

In this work, we report the physical properties of amorphous $Al_2O_3$ thin films by plasma-enhanced chemical vapour deposition (PECVD) using trimethyl-aluminium (TMA) as the Al precursor at low temperatures. The thin films were deposited on Si substrates. The composition and the bonding structure of the amorphous $Al_2O_3$ films were studied using Fourier transform infrared spectroscopy (FT-IR), Ellipsometer and UV-visible Spectrophotometer and MOCON.