• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.186.1-189
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• 2001

Ferroelectric $Bi_{4-x}$La$_{x}$Ti$_3$O$_{12}$ (BLT)thin films with various compositions(x=0.65, 0.70, 0.75) were prepared on Pt//Ti/SiO$_2$/Si(100) substrate by metal-organic deposition. The electrical and structural characteristics of BLT thin films were investigated to develop ferroelectric thin films for capacitor layers of FRAM. After spin coating, thin films were annealed at $650^{\circ}C$ for 1hour in oxygen atomosphere. Scanning electron micrographs showed uniform surfaces composed of rod-like grains. The $Bi_{4-x}$La$_{x}$Ti$_3$O$_{12}$ (x=0.70) thin film capacitors with a Pt top electrode showed better ferroelectric properties than other films. At the applied voltage of 5V, the dielectric constant($\varepsilon$$_{r}$), dissipation factor(tan$\delta$),remanent polarization(2Pr), and coercive field(2Ec) of the $Bi_{4-x}$La$_{x}$Ti$_3$O$_{12}$ (x=0.70)thin films were about 272.54, 0.059, 32.4 $\mu$C/cm$^2$, 2Ec=119.9kV/cm. Also the capacitor did not show any significant fatigue up to 4.8$\times$10$^{10}$ read/write switching cycles.hing cycles.s.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.6
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• pp.410-415
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• 1999

$Ba_{1-x}Sr_xTiO_3$ thin films with various ratio of Sr (X = 0.4, 0.5, 0.6) were grown $Pt/TiN/SiO_2/Si$ subastrate by RF magnetron sputtering deposition. As, Ag, and Cu films were deposited on $Ba_{1-x}Sr_xTiO_3$ thin films as top electrodes by using a thermal evaporator. The electrical properties of $Ba_{1-x}Sr_xTiO_3$ thin films for various compositions were characterized and the physical properties at interface between $Ba_{1-x}Sr_xTiO_3$ thin films and top electrodes were evaluated in terms of the work function difference. At x =0.5, the degradation of capacitance is lower to the other compositions. As negative biasapplied, the specimen with Cu top electrode has board saturation region and low leakage current since work function of Cu is bigger than other electrodes.$ Ba_{0.5}Sr_{0.5}TiO_3$ thin films with Cu top electrode, the dielectric constant was measured to the value of 354 at 1 kHz and the leakage current was obtained to the value of $5.26\times10^{-6}A/cm2$ at the forward bias of 2 V.

• Korean Journal of Materials Research
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• v.23 no.6
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• pp.334-338
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• 2013

In this study, $BaTiO_3$ thin films were grown by RF-magnetron sputtering, and the effects of the thin film thickness on the structural characteristics of $BaTiO_3$ thin films were systematically investigated. Instead of the oxide substrates generally used for the growth of $BaTiO_3$ thin films, p-Si substrates which are widely used in the current semiconductor processing, were used in this study in order to pursue high efficiency in device integration processing. For the crystallization of the grown thin films, annealing was carried out in air, and the annealing temperature was varied from $700^{\circ}C$. The changed thickness was within 200 nm~1200 nm. The XRD results showed that the best crystal quality was obtained for ample thicknesses 700 nm~1200 nm. The SEM analysis revealed that Si/$BaTiO_3$ are good quality interface characteristics within 300 nm when observed thickness. And surface roughness observed of $BaTiO_3$ thin films from AFM measurement are good quality surface characteristics within 300 nm. Depth-profiling analysis through GDS (glow discharge spectrometer) showed that the stoichiometric composition could be maintained. The results obtained in this study clearly revealed $BaTiO_3$ thin films grown on a p-Si substrate such as thin film thickness. The optimum thickness was 300 nm, the thin film was found to have the characteristics of thin film with good electrical properties.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.3
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• pp.195-201
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• 2003

The (Ba,Bi,Sr)TiO$_3$[BBST] thin films were fabricated on Pt/Ti/SiO$_2$ /Si substrate by RF sputtering method. The effects of Ar/O$_2$ ratio on the structural and dielectric properties of BBST thin films were investigated. Increasing the Ar/O$_2$ ratio, the intensity of BaBi$_4$Ti$_4$O$_{15}$ and Bi$_4$Ti$_3$O$_{12}$ peaks were increased but (Ba$_{0.5}$Sr$_{0.5}$)TiO$_3$ peak was decreased. In the BBST thin films deposited with condition of Ar/O$_2$(90/10) ratio, the composition ratio of the Ba, Bi and Sr atoms were 0.35, 0.25 and 0.4 respectively. The Bi and Ti atoms were diffused into the Pt layers. Increasing the Ar/O$_2$ ratio, the dielectric constant of the BBST thin films were increased but the dielectric loss of the BBST thin films were decreased. The dielectric constant and dielectric loss of the BBST deposited at 90/10 of Ar/O$_2$ ratio were 319 and 2.2%. respectively . Increasing the applied voltage, the capacitance of the BBST thin films were decreased.reased.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.2
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• pp.67-74
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• 2017

In this work, the effects of nano $TiO_2$ on functionality and stability of low density polyethylene (LDPE) composite films were investigated for food packaging application. LDPE-nano $TiO_2$ composite films were prepared with various $TiO_2$ contents (0, 0.5, 1.0, 3.0 and 5.0wt%) by melt-extrusion and their basic properties such as crystallinity, chemical bonds and surface morphology were examined by XRD, FTIR and SEM. Ultraviolet (UV) light barrier property of as-prepared LDPE-nano $TiO_2$ composite films was also studied and the presence of nano $TiO_2$ resulted in significant improvement of UV light barrier compared to the pure LDPE film. To evaluate influence of nano $TiO_2$ on LDPE properties required as packaging material, thermal, mechanical, gas barrier and optical properties of LDPE-nano $TiO_2$ composite films were characterized with various analytical techniques including TGA, UTM, OTR, WVTR and UV-vis spectroscopy. As a result, except optical property of LDPE, no significant effects were found in other properties. Opacity of pure LDPE was greatly increased with increasing concentration of nano $TiO_2$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.304-304
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• 2014

Quaternary Ti-Al-Si-N films were deposited on WC-Co substrates by a hybrid deposition system of arc ion plating (AIP) method for Ti-Al source and DC magnetron sputtering technique for Si incorporation. The synthesized Ti-Al-Si-N films were revealed to be composites of solid-solution (Ti,Al)N crystallites and amorphous $Si_3N_4$ by instrumental analyses. The Si addition in Ti-Al-N films affected the refinement and uniform distribution of crystallites by percolation phenomenon of amorphous silicon nitride, similarly to Si effect in TiN film. As the Si content increased up to about 9 at.%, the hardness of Ti-Al-N film steeply increased from 30 GPa to about 50 GPa. The highest microhardness value (~50 GPa) was obtained from the Ti-Al-Si-N film having the Si content of 9 at.%, the microstructure of which was characterized by a nanocomposite of $nc-(Ti,Al)N/a-Si_3N_4$.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.5
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• pp.324-329
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• 2000

Microstructure, mechanical and fatigue behaviors of TiCN and TiN/TiCN thin films, deposited on quenched and tempered STD61 tool steel, were investigated by using XRD, XPS, hardness, adhesion and fatigue tests. The TiCN thin film is grown along the (100), (111) orientation, whereas the TiN/TiCN thin film is grown along the (111) orientation. The preferred orientation of TiN/TiCN thin film strongly depends on the TiN buffer layer whose orientation is (111), as is well-known. The TiN/TiCN thin film showed the higher adhesion compared with TiCN single layer because the TiN buffer layer, having good toughness, reduces the effects of the lower hardness of substrate. In the high cycle tension-tension fatigue test, the fatigue life of the TiCN and the TiN/TiCN coated steel increased approximately two to four times and five to nine times respectively compared with uncoated specimens. The TiN buffer layer in multilayer thin films plays an important role in reducing residual stress and fatigue crack initiation, and then in restraining the fatigue propagation.

• Journal of the Korean institute of surface engineering
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• v.41 no.6
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• pp.287-291
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• 2008

Reactively magnetron sputtered TiN films were deposited on Si wafers under varying bias voltage and characterized by X-ray diffraction, field-emission scanning electron microscopy and Nanoindentation. The films deposited under an Ar + $N_2$ atmosphere exhibited a mixed (200)-(111) orientation with a strong (200) texture, which subsequently changed to a strong (111) texture with increasing bias voltage. The changes in texture and grain size of the TiN thin films are due to one or a combination of factors such as strain energy, surface free energy, surface diffusivity and adatom mobility. The influence of each factor depends on the processing conditions. The average deposition rate and grain size were calculated from FE-SEM images of the films indicating that the deposition rate was lower at the films deposited under bias voltage.

• Journal of the Korean Ceramic Society
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• v.33 no.2
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• pp.177-182
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• 1996

strontium titanate (SrTiO3) thin films deposited on Pt/MgO were prepared by Plasma Enhanced Metal Orgainc Chemical vapor Deposition (Pe-MOCVD). The crystallinity of SrTiO3 thin films increased with increasing depo-sition temperature and SrF2 second phase disappeared at 55$0^{\circ}C$ The films showed a dielectric constant of 177 and a dissipation factor of 0.0195 at 100 kHz. The variation of capacitance of the films with applied voltage was small showing paraelectric properties. The charge storage density and leakage current density were 40fC/${\mu}{\textrm}{m}$2 and 3.49$\times$10-7 A/cm2 at 0.25 MV/cm, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.189-193
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• 1997

(S $r_{0.85}$/C $a_{0.15}$)Ti $O_3$(SCT) thin films at various deposition temperature and rf power were grown by rf magnetron sputtering method on optimized Pt-based electrodes (Pt/TiN/ $SiO_2$/Si). The crystallinity of the films increases with increasing deposition temperature. SCT thin film is depend on the surface morphology and crystallinity of Pt films for bottom electrode. Dielectric constant of (S $r_{0.85}$C $a_{0.15}$)Ti $O_3$ thin films deposited on Si wafer substrate are larger with the increase of deposition temperature and gain size.in size.