• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.4
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• pp.203-208
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• 2014

In this study, Sputtering method was used to grow Al-dopes ZnO films on a CIGS absorber layer, in order to examine the effect of TCO on properties of CIGS solar cell devices. Structural, electrical and optical properties were investigated by varied thickness of Al-dopes ZnO films. Also, relation to the application as a window layer in CIGS thin film solar cell were studied. It was found that the electrical and structural properties of ZnO:Al film improved with increasing its thickness. However, the optical properties degraded. Jsc of the fabricated CIGS based solar cells was significantly influenced by the variation of the ZnO:Al window layer thickness. Because ZnO:Al window layer is one of the Rs factors in CIGS solar cell. Rs has the biggest influence on efficiency characteristic. In order to obtain high efficiency of CIGS solar cell, ZnO:Al window layer should be fabricated with electrically and optically optimized.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1393-1398
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• 2015

In this study, the electrical and optical properties of GZO (Ga-doped ZnO) thin films prepared on PES substrates by RF magnetron sputtering method with various working pressures (5 to 20 mTorr) were investigated. All GZO thin films exhibited c-axis preferential growth regardless of working pressure, the GZO thin film deposited at 5 mTorr showed the most excellent crystallinity having 0.44˚ of FWHM. In AFM observations, surface roughness exhibited the lowest value of 0.20 nm in a thin film produced by the working pressure 5 mTorr. Figure of merits of GZO thin film deposited at 5 mTorr showed the highest value of 6652, in this case resistivity and average transmittance in the visible light region were 6.93×10^-4Ω-cm and 81.4%, respectively. We could observed the Burstein-Moss effect that carrier concentration decrease with the increase of working pressure and thus the energy band gap is narrowed.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1096_1097
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• 2009

Aluminium doped zinc oxide(ZnO:Al) thin film, which is mainly used as a transparent conducting electrode in electronic devices, has many advantages compared with conventional indium tin oxide(ITO). In this paper in order to investigate the possible application of ZnO:Al thin films as a transparent conducting electrode for flexible film-typed dye sensitized solar cell (FT-DSCs), ZnO:Al and ITO thin films were prepared on the polyethylene terephthalate (PET) substrate by r. f. magnetron sputtering method. Specially one-inched FT-DSCs using either a ZnO:Al or ITO electrode were also fabricated separately under the same manufacturing conditions. Some properties of both the FT-DSCs with ZnO:Al and ITO transparent electrodes, such as conversion efficiency, fill factor, and photocurrent were measured and compared with each other. The results showed that by doping the ZnO target with 2 wt% of $Al_2O_3$, the film deposited at discharge power of 200W resulted in the minimum resistivity of $2.2\times10^{-3}\Omega/cm$ and at ransmittance of 91.7%, which are comparable with those of commercially available ITO. Two types of FT-DSCs showed nearly the same tendency of I-V characteristics and the same value of conversion efficiencies. Efficiency of FT-DSCs using ZnO:Al electrode was around 2.6% and that of fabricated FT-DSCs using ITO was 2.5%. This means that ZnO:Al thin film can be used in FT-DSCs as a transparent conducting layer.

• Journal of Sensor Science and Technology
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• v.10 no.3
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• pp.173-179
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• 2001

The currently used semiconductor pressure sensors are piezoresistive and capacitive type. Especially, semiconductor micro pressure sensors have a great deal of attention because of their small size. However, its fabrication processes are difficult, so that its yield is poor. For the purpose of resolving the drawbacks of the existing silicon pressure sensors, we demonstrate a new type of pressure sensor using PSFET(pressure sensitive field effect transistor) and investigate its operational characteristics. We used PZT(Pb(Zr,Ti)$O_3$) as a pressure sensing material. PZT thin films were deposited on a gate oxide of MOSFET by an rf-magnetron sputtering method. To abtain the stable phase, perovskite structure, furnace annealing technique have been employed in PbO ambient. The sensitivity of the PSFET was 0.38 mV/mmHg.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.67-68
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• 2006

Floating gate non-volatile memory devices with Au nano-particles embedded in SiON or $SiO_2$ dielectrics were fabricated by digital sputtering method. The size and the density of Au are 4nm and $2{\times}10^{-12}cm^{-2}$, respectively. The floating gate memory of MOSFET with 5nm tunnel oxide and 45nm control oxide have been fabricated. This devices revealed a memory effect which due to proGrainming and erasing works perform by a gate bias stress repeatedly.

• Korean Journal of Materials Research
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• v.24 no.4
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• pp.194-200
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• 2014

Metallic Cr film coatings of $1.2{\mu}m$ thickness were prepared by DC magnetron sputter deposition method on c-plane sapphire substrates. The thin Cr films were ammoniated during horizontal furnace thermal annealing for 10-240 min in $NH_3$ gas flow conditions between 400 and $900^{\circ}C$. After annealing, changes in the crystal phase and chemical constituents of the films were characterized using X-ray diffraction (XRD) and energy dispersive X-ray photoelectron spectroscopy (XPS) surface analysis. Nitridation of the metallic Cr films begins at $500^{\circ}C$ and with further increases in annealing temperature not only chromium nitrides ($Cr_2N$ and CrN) but also chromium oxide ($Cr_2O_3$) was detected. The oxygen in the films originated from contamination during the film formation. With further increase of temperature above $800^{\circ}C$, the nitrogen species were sufficiently supplied to the film's surface and transformed to the single-phase of CrN. However, the CrN phase was only available in a very small process window owing to the oxygen contamination during the sputter deposition. From the XPS analysis, the atomic concentration of oxygen in the as-deposited film was about 40 at% and decreased to the value of 15 at% with increase in annealing temperature up to $900^{\circ}C$, while the nitrogen concentration was increased to 42 at%.

• Journal of the Korean Magnetics Society
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• v.13 no.2
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• pp.47-52
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• 2003

Ferromagnetic tunnel junctions were fabricated by dc magnetron sputtering and plasma oxidation process. The local transport properties of the ferromagnetic tunnel junctions were studied using contact-mode Atomic Force Microscopy (AFM) and the local current-voltage analysis. Tunnel junctions with the structure of sub./Ta/Cu/Ta/NiFe/Cu/Mn$\_$75/Ir$\_$25//Co$\_$70/Fe$\_$30//Al-oxide were prepared on thermally oxidized Si wafers. Al-oxide layers were formed with microwave excited plasma using radial line slot antenna (RLSA) for 5 and 7 sec. Kr gas was used as the inert gas mixed with $O_2$ gas for the plasma oxidization. No correlation between topography and current image was observed while they were measured simultaneously. The local current distribution was well identified with the distribution of local barrier height. Assuming the gaussian distribution of the local barrier height, the ferromagnetic tunnel junction with longer oxidation time was well fitted with the experimental results. As contrast, in the case of the shorter time oxidation junction, the current mainly flow through the low barrier height area for its insufficient oxygen. Such leakage current might result in the decrease of tunnel magnetoresistance (TMR) ratio.

• Journal of the Korean Magnetics Society
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• v.18 no.5
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• pp.190-194
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• 2008

Epitaxial $L1_0$ FePd (001) thin films were successfully manufactured by sputtering deposition method. The structure and magnetic properties of FePd thin films were characterized as a function of Fe compositions. It was found that the long-range ordering parameter had a maximum for the stoichiometric composition, whereas the magnetic anisotropy had a maximum as the Fe content is decreased to slightly above the stoichiometric composition. This indicates that the stoichiometry is directly contributed to the chemical ordering and the magnetic anisotropy. These results imply that nonstoichiometric FePd compositions, with a slight excess of Pd, may in fact be preferred for applications that require high magnetic anisotropy.

• Journal of Information Display
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• v.6 no.3
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• pp.18-21
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• 2005

A new technology for reducing photolithography process from a four step to a three step process in the fabrication of TFT LCD is introduced. The core technology for 3-mask-TFT processes is the lift-off process [1], by which the PAS and PXL layers can be formed simultaneously. A different method of the lift-off process was developed in order to enhance the performance of efficiency with conventional positive and not negative PR which is the generally used in other lift-off process. In addition, the removal capacity of the ITO/PR in lift-off process was evaluated. The evaluation results showed that the new process can be run in conventional TFT production condition. In order to apply this new process in existing TFT process, several tests were conducted to ensure stability of the TFT process. It was found that the outgases from PR on the substrate in ITO sputtering chamber do not raise any problem, and the deposited ITO film beside the PR has conventional ITO qualities. Furthemore, the particles that were produced due to the ITO chips in PR strip bath could be reduced by the existing filtering system of stripper. With the development of total process and design of the structure for TFT using this technology, 3-mask-panels were achieved in TN and IPS modes, which showed the same display performances as those with the conventional 4mask process. The applicability and usefulness of the 3-mask process has already verified in the mass production line and in fact it currently being used for the production of some products.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.2
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• pp.177-184
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• 1996

We adopted the $Pt/SiO_{2}/Si$ and the $Ir/SiO_{2}/Si$ substrates of which buffer layer is $PbTiO_{3}$ to improve electrode and interfacial properties of PZT thin film deposited by reactive sputtering method using metal target in this study. We got PZT thin film to have highly oriented(100) structure and good crystallinity using buffer layer in Pt bottom-electrode, though randomly oriented PZT thin film was obtained without buffer layer. Although great improvement of PZT phase formation on Ir bottom-electrode with buffer layer was not observed, we observed the increase of remennant polarization and the decrease of coercive field compared with properties of PZT thin films on the Pt bottom-electrode. So we got the results of the increase of dielectric constant using buffer layer on fabrication of PZT thin film and the better dielectric properties in PZT thin film using Ir bottom-electrode compared with that using Pt bottom-electrode.