• Journal of the Semiconductor & Display Technology
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• v.4 no.1 s.10
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• pp.55-59
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• 2005

The ($Sr_{1-x}Ca_{x})Ti_{3}$(SCT) thin film are deposited on Pt-coated electrode (Pt/TiN/$SiO_{2}$/Si) using RF sputtering method. The maximum dielectric constant of SCT thin film is obtained by annealing at 600[$^{\circ}C$]. The temperature properties of the dielectric loss have a value within 0.02 in temperature lunges of -80 $\∼$ +90[$^{\circ}C$]). The capacitance characteristics had a stable value within ${\pm}4\%$. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films is observed above 200[kHz).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.186-189
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• 2003

The MFIS capacitors were fabricated using a metalorganic decomposition method. Thin layers of $ZrO_2$ and $CeO_2$ were deposited as a buffer layer on Si substrate and BLT thin films were used as a ferroelectric layer. The electrical and structural properties of the MFIS structure were investigated. X -ray diffraction was used to determine the phase of the BLT thin films and the quality of the $ZrO_2$ and $CeO_2$ layer. AES show no interdiffusion and the formation of amorphous $SiO_2$ layer is suppressed by using the $ZrO_2$ and $CeO_2$ film as buffer layer between the BLT film and Si substrate. The width of the memory window in the C-V curves for the $BLT/ZrO_2/Si$ and $BLT/CeO_2/Si$ structure is 2.94 V and 1.3V, respectively. The experimental results show that the BLT-based MFIS structure is suitable for non-volatile memory FETs with large memory window.

• Korean Journal of Materials Research
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• v.4 no.4
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• pp.416-427
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• 1994

The changes of crystallinity and microstructure and the $Si_{1-x}Ge_x/Sio_2$ interfaces of $Si_{1-x}Ge_x$ alloys deposited on amorphous $SiO_{2}$ were studied as a function of deposition temperature. The crystallinity, microstructure, and compositional uniformity of $Si_{1-x}Ge_x$ alloys deposited on the SiOl at different temperature were investigated by X-ray diffraction and transmission electron microscopy. And $Si_{1-x}Ge_x/Sio_2$ interface were investigated by high-resolution transmission electron microscopy. The $Si_{0.7}Ge_{0.3}/Sio_2$ films were deposited on amorphous $SiO_{2}$ at $300^{\circ}C,400^{\circ}C,500^{\circ}C,600^{\circ}C,$ and $700^{\circ}C$ by Si-MBE. In the film deposited at $300^{\circ}C$, only amorphous phase were observed. In the film deposited at $400^{\circ}C$, both amorphous and polycrystalline films were observed. Both phases were deposited simultaneously, but, at initial film growth, amorphous phase prevailed over polycrystalline phase. As the film thickness increased, the fraction of polycrystalline phase increased. At $500^{\circ}C$, thin amorphous layer was observed at lOnm from $SiO_{2}$ surface. In the films deposited at higher than $600^{\circ}C$, only crystalline phase were observed. Polycrystalline films had columnar structure. Compositional uniformity for deposited films were good regardless of deposition temperature. The interfaces of $Si_{1-x}Ge_x/Sio_2$ were flat, whatever polycrystal or amorphous was deposited on $SiO_{2}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.2
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• pp.121-124
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• 2012

The characteristics of Ga-doped zinc oxide (GZO) thin films deposited at different deposition temperatures (TS~250 to $550^{\circ}C$) on 4H-SiC have been investigated. Structural and electrical properties of GZO thin film on n-type 4H-SiC(0001) were investigated by using x-ray diffraction(XRD), atomic force microscopy(AFM), Hall effect measurement, barrier height from I-V curve and Auger electron spectroscopy(AES). XRD $2\theta$ scan shows GZO thin film has preferential orientation with c-axis perpendicular to SiC substrate surface. The lowest resistivity ($\sim1.9{\times}10^{-4}{\Omega}cm$) was observed for the GZO thin film deposited at $400^{\circ}C$. As deposition temperature increases, barrier height between GZO and SiC was increased. Whereas, resistivity of GZO thin films as well as barrier height between GZO and SiC were increased after annealing process in air atmosphere. It has been found that the c-axis oriented crystalline quality as well as the relative amount of activated Ga3+ ions and oxygen vacancy may affect the electrical properties of GZO films on SiC.

• Korean Journal of Materials Research
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• v.27 no.8
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• pp.403-408
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• 2017

We investigated the effect of ZnO buffer layer on the formation of ZnO thin film by ultrasonic assisted spray pyrolysis deposition. ZnO buffer layer was formed by wet solution method, which was repeated several times. Structural and optical properties of the ZnO thin films deposited on the ZnO buffer layers with various cycles and at various temperatures were investigated by field-emission scanning electron microscopy, X-ray diffraction, and photoluminescence spectrum analysis. The structural investigations showed that three-dimensional island shaped ZnO was formed on the bare Si substrate without buffer layers, while two-dimensional ZnO thin film was deposited on the ZnO buffer layers. In addition, structural and optical investigations showed that the crystalline quality of ZnO thin film was improved by introducing the buffer layers. This improvement was attributed to the modulation of the surface energy of the Si surface by the ZnO buffer layer, which finally resulted in a modification of the growth mode from three to two-dimensional.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.119-119
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• 2015

Ion beam sputtering has been widely used in Secondary Ion Mass Spectrometry (SIMS), X-ray Photoelectron Spectroscopy (XPS), and Auger Electron Spectroscopy (AES) for depth profile or surface cleaning. However, mainly due to severe matrix effects such as surface composition change from its original composition and damage of the surface generated by ion beam bombardment, conventional sputtering skills using mono-atomic primary ions with energy ranging from a few hundred to a thousand volts are not sufficient for the practical surface analysis of next-generation organic/inorganic device materials characterization. Therefore, minimization of the surface matrix effects caused by the ion beam sputtering is one of the key factors in surface analysis. In this work, the electronic structure of a $Ta_2O_5$ thin film on $SiO_2/Si$ (100) after Ar Gas Cluster Ion Beam (GCIB) sputtering was investigated using X-ray photoemission spectroscopy and compared with those obtained via mono-atomic Ar ion beam sputtering. The Ar ion sputtering had a great deal of influence on the electronic structure of the oxide thin film. Ar GCIB sputtering without sample rotation also affected the electronic structure of the oxide thin film. However, Ar GCIB sputtering during sample rotation did not exhibit any significant transition of the electronic structure of the $Ta_2O_5$ thin films. Our results showed that Ar GCIB can be useful for potential applications of oxide materials with sample rotation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.371-374
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• 2002

Bismuth lanthanum titanate thin films with excess Bi contents were prepared onto Pt/Ti/$SiO_2$/Si substrate by metalorganic decomposition (MOD) technique. The structure and morphology of the films were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. From the XRD analysis, BLT thin films show polycrystalline structure and the layered-perovskite phase was obtained over 10% excess of Bi contents. As a result of ferroelectric characteristics related to the Bi content of the BLT thin film, the remanent polarization and dielectric constant decreased with increasing over Bi content of 10 % excess. The BLT film with Bi content of 10% excess was measured to have a dielectric constant of n9 and dielectric loss of 1.85[%]. The BLT thin films showed little polarization fatigue test up to 3.5 x $10^{9}$ bipolar switching cycling.

• Korean Journal of Materials Research
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• v.8 no.10
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• pp.961-968
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• 1998

In order to investigate the effects of substrate bias voltage on the formation of$ZnS-SiO_2$ protective film in phase change optical disk by R.F. magnetron sputtering method, thin dielectric film was formed on Si wafer and Corning glass by using ZnS(80mol%)-$SiO_2$(20mol%)t arget under argon gas. In this study, the Taguchi experimental method was applied in order to obtain optimum conditions with reduced number of experiments and to control numerous variables effectively. At the same time this method can assure the reproducibility of experiments. Optimum conditions for film formation obtained by above method were target RF power of 200 W. substrate RF power of 20 W, Ar pressure of 5 mTorr. sputtering time of 20 min.. respectively. The phase of specimen was determined by using XRD and TEM. The compositional analysis of specimen was performed by XPS test. In order to measure the thermal resistivity of deposited specimen, annealing test was carried out at $300^{\circ}C$ and $600^{\circ}C$. For the account of void fraction in thin film, the Bruggeman EMA(Effective Medium Approximation) method was applied using the optical data obtained by Spectroscopic Ellipsometry. According to the results of this work, the existence of strong interaction between bias voltage and sputtering time was confirmed for refractive index value. According to XRD and TEM analysis of specimen, the film structure formed in bias voltage resulted in more refined structures than that formed without bias voltage. But excess bias voltage resulted in grain growth in thin film. It was confirmed that the application of optimum bias voltage increased film density by reduction of void fraction of about 3.7%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.19-19
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• 2009

TiNxOy/TiNx multilayer thin films with a high resistance (~ k$Omega$) were deposited on SiO2/Si substrates at room temperature by sputtering. The TiNx thin films show island and smooth surface morphology in samples prepared by dc and rf magnetron sputtering, respectively. TiNxOy/TiNx multilayer has been developed to control temperature coefficient of resistance (TCR) by the incorporation of TiNx layer (positive TCR) inserted into TiNxOy layers(negative TCR). Electrical and structural properties of sputtered TiNxOy/TiNx multilayer films were investigated as a function of annealing temperature. In order to achieve a stable high resistivity, multilayer films were annealed at various temperatures in oxygen ambient. Samples annealed at 700 oC for 1 min exhibit a good TCR value and a stable high resistivity.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.7
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• pp.914-918
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• 1995

In this study, Pb(Zr$_{x}$ Ti$_{1-x}$ )O$_{3}$ (x=0.65, 0.52, 0.35) thin films were fabricated by Sol-Gel method. A stock solution with excess Pb 10[mol%] of Pb(Zr$_{x}$ Ti$_{1-x}$ )O$_{3}$ was made and spin-coated on the Pt/SiO$_{2}$/Si substrate at 4000[rpm] for 30[sec.]. Coated specimens were dried on the hot-plate at 400[.deg. C] for 10[min.]. Sintering temperature and time were 500~800[.deg. C] and 1~60[min.]. The coating process was repeated 6 times and the final thickness of the thin films were about 4800[A]. To investigate crystallization condition, PZT thin films were analyzed with sintering temperature, time and composition by the XRD. The microstructure of thin fulms were investigated by SEM. The ferroelectric perovskite phases precipitated under the sintering of 700[.deg. C] for 1 hours. In the PZT(52/48) composition, dielectric constant and dielectric loss were 2133, 2.2[%] at room temperature, respectively.ively.