• Transactions on Electrical and Electronic Materials
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• v.12 no.2
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• pp.76-79
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• 2011

In order to improve efficiency and make a new material thin film, we prepared the Al-In-Sn-ZnO thin film on a glass substrate at room temperature using a Facing Target Sputtering (FTS) system. The FTS system was designed to array two targets that face each other. Two different kinds of targets were installed on the FTS system. We used an ITO ($In_2O_3$ 90wt%, $SnO_2$ 10wt%) target and an AZO (ZnO 98wt%, $Al_2O_3$ 2wt%) target. The AIZTO films were deposited using different applied powers to the targets. The as-deposited AIZTO thin films were investigated using a UV/VIS spectrometer, an X-ray diffratometer (XRD), and Energy Dispersive X-ray spectroscopy (EDX).

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.329.1-329.1
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• 2014

In this paper, we report electrical, optical and structural properties of Al-doped zinc oxide (AZO) thin films deposited at different substrate temperatures and pressures. The films were prepared by radio frequency (RF) magnetron sputtering on glass substrates in argon (Ar) ambient. The X-ray diffraction analysis showed that the AZO films deposited at room temperature (RT) and 20 Pa were mostly oriented along a-axis with preferred orientation along (100) direction. There was an improvement in resistivity ($3.7{\times}10^{-3}{\Omega}-cm$) transmittance (95%) at constant substrate temperature (RT) and working pressure (20 Pa) using the Hall-effect measurement system and UV-vis spectroscopy, respectively. Our results have promising applications in low-cost transparent electronics, such as the thin-film solar cells and thin-film transistors due to favourable deposition conditions. Furthermore our film deposition method offers a procedure for preparing highly oriented (100) AZO films.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.304.2-304.2
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• 2016

Hafnium oxide-aluminum oxide (HfO2-Al2O3) dielectric films have been fabricated by Pulsed Laser Deposition (PLD), and their properties are studied in comparison with HfO2 films. As a gate dielectric of the TFT, in spite of its high dielectric constant, HfO2 has a small energy band gap and microcrystalline structure with rough surface characteristics. When fabricated by the device, it has the drawback of generating a high leakage current. In this study, the HfAlO films was obtained by Pulsed Laser Deposition with HfO2-Al2O3 target(chemical composition of (HfO2)86wt%(Al2O3)14wt%). The characteristics of the thin Film have been investigated by x-ray diffraction (XRD), atomic force microscopy (AFM) and spectroscopic ellipsometer (SE) analyses. The X-ray diffraction studies confirmed that the HfAlO has amorphous structure. The RMS value can be compared to the surface roughness via AFM analysis, it showed HfAlO thin Film has more lower properties than HfO2. The energy band gap (Eg) deduced by spectroscopic ellipsometer was increased. HfAlO films was expected to improved the interface quality between channel and gate insulator. Apply to an oxide thin Film Transistors, HfAlO may help improve the properties of device.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.46.2-46.2
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• 2010

For use of superstrate thin-film solar cells, surface texture of the transparent conductive oxide (TCO) has been used to enhance short-circuit currents by increasing light trapping into the cell. ZnO:Al films were deposited by using DC magnetron sputtering on glass substrates with ceramic (ZnO:$Al_2O_3$) target. The as-deposited TCO before texturing exhibited high transparencies (T > 85% for visible light including all reflection losses) and excellent electrical properties ($r=3-6{\times}10^{-4}{\Omega}.cm$). The optical and electrical properties of the TCO are influenced by the texturing conditions such as not only etchant dilutions but also etching time. We obtained the haze value of 14-16 resulting in increase in light trapping and short-circuit currents also.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1568-1570
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• 2003

We have studied the I-V characteristics of polytetrafluoroethylene(PTFE) thin film depending on a variation of thickness. Polymer PTFE buffer layer was made using thermal evaporation technique. The device was made in the structure of ITO/PTFE/Al. We have observed the NDR(negative differential resistance) behavior between 2.5V and 5V. There are some reports on this NDR behavior in the polymer thin film[1]. We have studied the NDR behavior depending on a variation thickness. As the film thickness increased, The NDR behavior decreased and moved in low electrical field, and we have studied the conduction mechanism of PTFE thin film.

• Journal of Information Display
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• v.10 no.1
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• pp.24-27
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• 2009

A simple nonalkoxide sol-gel route for depositing an Al-doped ZnO thin film on a glass substrate was derived in this study. The initial Al dopant concentration in the sol-gel preparation varied and ranged from 0 to 5%. The sol-gel-derived thin films showed c-plane preferred crystallization of their hexagonal phase, with nanosized grain structures. First and second post-heat-treatments were carried out to improve the film’s electrical resistivity. The carrier density and the Hall mobility were measured and discussed to explain the electrical resistivity. The optical transmittance within the visible range showed compatible properties, which indicates the possible use of A1-doped ZnO as a transparent electrode in flat panel displays.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.703-706
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• 2002

Piezoelectric thin film such as ZnO and AlN can be applicable to FBAR (Film Bulk Acoustic Resonator) device of thin film type and FBAR can be applicable to MMIC. The characteristic of FBAR device is variable according to the deposition conditions of piezoelectric thin film when preparation of thin film by sputtering method. In this study, we prepared ZnO thin film for FBAR using Facing Targets Sputtering apparatus which can be deposited fine Quality thin film because temperature increase of substrate due to the bombardment of high-energy particles can be restrained. And crystalline and c-axis preferred orientation of ZnO thin film with deposition conditions was investigated by XRD.

• Journal of Information Display
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• v.5 no.3
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• pp.30-34
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• 2004

Fabrications of barrier layer on a polyethersulfon (PES) film and OLED based on a plastic substrate by atomic layer deposition (ALD) have been carried out. Simultaneous deposition of 30 nm of $AlO_x$ film on both sides of PES film gave film MOCON value of 0.0615 g/$m^2$/day (@38$^{\circ}C$, 100 % R.H.). Moreover, the double layer of 200 urn $SiN_x$ film deposited by PECVD and 20 nm of $AlO_x$ film by ALD resulted in the MOCON value lower than the detection limit of MOCON. The OLED encapsulation performance of the double layer have been investigated using the OLED structure of ITO/MTDATA(20 nm)/NPD(40 nm)/AlQ(60 nm)/LiF(1 nm)/Al(75 nm) based on the plastic substrate. Preliminary life time to 91 % of initial luminance (1300 cd/$m^2$) was 260 hours for the OLED encapsulated with 100 nm of PECVD deposited $SiN_x$/30 nm of ALD deposited $AlO_x$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.252-252
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• 2009

In this work, the nanocrystalline ZnO/polycrystalline (poly) aluminum nitride (AlN)/Si structure was fabricated for humidity sensor applications based on surface acoustic wave (SAW). In this structure, the ZnO film was used as sensing material layer. These ZnO and AlN(0002) were deposited by so-gel process and a pulse reactive magnetron sputtering, respectively. These experimental results showed that the obtained SAW velocity on AlN film was about 5128 m/s at $h/\lambda$=0.0125 (h and $\lambda$ is thickness and wavelength, respectively). For ZnO sensing layers coated on AlN, films have hexagonal wurtzite structure and nanometer particle size. The crystalline size of ZnO films annealed at 400, 500, and 600 $^{\circ}C$ is 10.2, 29.1, and 38 nm, respectively. Surface of the film exhibits spongy which can adsorb steam in the air. The best quality of the ZnO film was obtained with annealing temperature at 500 $^{\circ}Cis$. The change in frequency response (127.9~127.85 MHz) of the SAW humidity sensor based on ZnO/AlN structure was measured along the change in humidity (41~69%). The structural properties of thin films wereinvestigated by XRD and SEM.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.7
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• pp.543-551
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• 2012

In this study, transparent conducting Al-doped Zinc Oxide (AZO) films with a thickness of 150 nm were prepared on corning glass substrate by the RF magnetron sputtering with using a Al-doped zinc oxide (AZO), ($Al_2O_3$: 2 wt%) target at room temperature. This study investigated the effect of rapid thermal annealing temperature and oxygen ambient on structural, electrical and optical properties of Al-doped zinc oxide (AZO) thin films. The films were annealed at temperatures ranging from 400 to $700^{\circ}C$ by using Rapid thermal equipment in oxygen ambient. The effect of RTA treatment on the structural properties were studied by x-ray diffraction and atomic force microscopy. It is observed that the Al-doped zinc oxide (AZO) thin film annealed at $500^{\circ}C$ at 5 minute oxygen ambient gas reveals the strongest XRD emission intensity and narrowest full width at half maximum among the temperature studied. The enhanced UV emission from the film annealed at $500^{\circ}C$ at 5 minute oxygen ambient gas is attributed to the improved crystalline quality of Al-doped zinc oxide (AZO) thin film due to the effective relaxation of residual compressive stress and achieving maximum grain size.