• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.1
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• pp.65-69
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• 2003

ZnO-Si-ZnO multi-layer thin films have been deposited by pulsed laser deposition (PLD). And then, the films have been annealed at 300$^{\circ}C$ in oxygen ambient pressure. Peak positions of ultraviolet (UV) and visible region were changed by addition of Si layer. Mobility of the films was improved slightly than ZnO thin film without Si layer. The structural property changed by inserting intermediate Si layer in ZnO thin film. The optical properties and structural properties of ZnO-Si-ZnO multi-layer thin films were characterized by PL(Photoluminescence) and XRB(X-ray diffraction) method, respectively. Electrical properties were measured by van der Pauw Hall measurements

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1057-1059
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• 2002

ZnO-Si-ZnO multi-layer thin films have been deposited by pulsed laser deposition (PLD). And then, the films have been annealed at $300^{\circ}C$ in oxygen ambient pressure. Electrical properties of the films were improved slightly than ZnO thin film without Si layer. Also, the optical and structural properties changed by Si layer in ZnO thin film. The optical and structural properties of Si-doped ZnO thin films were characterized by PL(Photoluminescence) and XRD(X-ray diffraction method) respectively. Electrical properties were measured by van der Pauw Hall measurements.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.4
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• pp.502-506
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• 2012

In order to find the structural characteristics of the thin films of group II-VI semiconductor compounds compared with those of powder materials, films were made of 4 powders of ZnS, CdS, CdSe, and CdTe(Aldrich), each with 99.99 % purity. For the ZnS/CdS multi-layers, the ZnS layer was coated over the CdS layer on an $AlO_x$ membrane, which served as a protective layer within a vacuum at the average speed of 1 ${\AA}$/sec. After studying the structures of the group II-VI semiconductor thin films by using X-ray spectroscopy, we found that the ZnS, ZnS/CdS, CdS, and CdSe films were hexagonal and exhibited some degree of preferred orientation. Also, the particles of the thin films of II-VI semiconductor compounds proved to be more homogeneous in size compared to those of the powder materials. These results were further verified through scanning electron microscopy(SEM), EDX analysis, and powder and thin film X-ray diffraction.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.9
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• pp.417-422
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• 2002

ZnO thin films were deposited on various substrates, such as Si-(111), SiO$_2$(5000 $\AA$ by thermal CVD)/Si-(100), and SiO$_2$(2000 $\AA$ by RF sputtering)/Si-(100). The (002)-orientation, surface morphology and roughness, and electrical resistivity of deposited films were measured and compared in terms of substrate. Surface acoustic wave(SAW) filters with a multilayered configuration of IDT/ZnO/SiO$_2$/Si were also fabricated and the IDT was obtained using a lift-off method. From the frequency-response characteristics of fabricated devices, the insertion loss and side-lobe rejection were estimated. The experimental results showed that the (002)-oriented growth nature of ZnO films, which played a crucial role of determining the characteristic of SAW device, was strong1y dependent upon the SiO$_2$buffer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.7-11
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• 2015

In this study, $Si_3N_4$/SnZnO/AZO/Ag/Ti/ITO multi-layer film were prepared on glass substrate by DC/RF magnetron sputtering method. To prevent interfacial reaction between Ag and ITO layer, Ti buffer layer was inserted. Optical properties and sheet resistance were studied depending on laminating times of each multi-layered film especially in visible ray. The simulation program, EMP (essential macleod program), was adopted and compared with experimental data to expect the experimental result. It was found out that the transmittance of the first stacked $Si_3N_4$/SnZnO/AZO/Ag/Ti/ITO multi-layer film was more than 90%. However, with increasing stacking times, the optical properties of $Si_3N_4$/SnZnO/AZO/Ag/Ti/ITO multi-layer film get worse. Consequently, Ti layer is good for oxidation barrier, but too many uses of this layer may have an adverse effect to optical properties of TCO film.

• Korean Journal of Optics and Photonics
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• v.12 no.5
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• pp.394-400
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• 2001

We studied thermal diffusion properties diffusion properties of multi-layered Ge-Sb-Te alloy thin films for optical recording media by solving the thermal equation. Based on the numerical analysis of optical energy distribution and absorption inside multi-layered films including temperature gradient and heat transfer simultaneously, we proposed the optimum parameters of the input laser power and the multi-layer structure as follow. i) Input laser power is 18 mW, ii) laser exposure time is 60 ns, iii) the thicknesses of the lower and the upper ZnS-SiO$_2$are 140 nm and 20~30 nm respectively, and iv) thickness of Ge-Sb-Te recording film is 20 nm.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.127-131
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• 2005

We report a nanometer scale mark formation using a $PtO_x$ thin film or a TbFeCo rare-earth transition metal film and the mechanism. The multi-layer samples($ZnS-SiO_2/PtOx/ZNS-SiO_2,\;ZnS-SiO_2/TbFeCo/ZnS-SiO_2$) were prepared with a magnetron sputtering method on a polycarbonate or a glass substrate. By laser irradiation of approximately a few nanoseconds, nanometer scale marks were fabricated. During the fabrication process, the thin films were thermally reacted or inter-diffused during the laser irradiation. 75 nm bubble marks in the PtOx multi-layer sample by an approximately 4-ns laser irradiation. Inside the bubble mark, Pt particles with a few nanometer sizes are distributed. The $50{\sim}100$ nm bubble marks in the TbFeCo multi-layer sample by a few nanosecond laser irradiations. We will report the detail structure of the samples, the bubble mark formation process and the mechanism.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.200-200
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• 2010

In recent times, metal oxide semiconductors thin films transistor (TFT), such as zinc and indium based oxide TFTs, have attracted considerable attention because of their several advantageous electrical and optical properties. There are many deposition methods for fabrication of ZnO-based materials such as chemical vapor deposition, RF/DC sputtering and pulsed laser deposition. However, these vacuum process require expensive equipment and result in high manufacturing costs. Also, the methods is difficult to fabricate various multicomponent oxide semiconductor. Recently, several groups report solution processed metal oxide TFTs for low cost and non vacuum process. In this study, we have newly developed solution-processed TFTs based on Ti-related multi-component transparent oxide, i. e., InTiO as the active layer. We propose new multicomponent oxide, Titanium indium oxide(TiInO), to fabricate the high performance TFT through the sol-gel method. We investigated the influence of relative compositions of Ti on the electrical properties. Indium nitrate hydrate [$In(NO^3).xH_2O$] and Titanium isobutoxide [$C_{16}H_{36}O_4Ti$] were dissolved in acetylacetone. Then monoethanolamine (MEA) and acetic acid ($CH_3COOH$) were added to the solution. The molar concentration of indium was kept as 0.1 mol concentration and the amount of Ti was varied according to weighting percent (0, 5, 10%). The complex solutions become clear and homogeneous after stirring for 24 hours. Heavily boron (p+) doped Si wafer with 100nm thermally grown $SiO_2$ serve as the gate and gate dielectric of the TFT, respectively. TiInO thin films were deposited using the sol-gel solution by the spin-coating method. After coating, the films annealed in a tube furnace at $500^{\circ}C$ for 1hour under oxygen ambient. The 5% Ti-doped InO TFT had a field-effect mobility $1.15cm^2/V{\cdot}S$, a threshold voltage of 4.73 V, an on/off current ratio grater than $10^7$, and a subthreshold slop of 0.49 V/dec. The 10% Ti-doped InO TFT had a field-effect mobility $1.03\;cm^2/V{\cdot}S$, a threshold voltage of 1.87 V, an on/off current ration grater than $10^7$, and a subthreshold slop of 0.67 V/dec.