• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.9
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• pp.760-765
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• 2011

Znic sulfide (ZnS) thin films were deposited on glass substrates by radio frequency magnetron sputtering. The substrate temperature varied from room temperature (RT) to $500^{\circ}C$. The structural and optical properties of ZnS films were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive analysis of X-ray (EDAX) and UV-visible transmission spectra. The XRD analyses reveal that ZnS films have cubic structures with (111) preferential orientation, whereas the diffraction patterns sharpen with the increase in substrate temperatures. The FESEM images indicate that ZnS films deposited at $400^{\circ}C$ have nano-sized grains with a grain size of ~ 67 nm. Then films exhibit relatively high transmittance of 80% in the visible region, with an energy band gap of 3.71 eV. One obvious result is that the energy band gap of the film increases with increasing the substrate temperatures.

• 연구논문집
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• s.31
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• pp.113-125
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• 2001

Silicon addition in titanium alloys generally results in solid solution hardening by silicon itself and precipitation hardening by titanium silicides. The morphology and distribution of the titanium silicides depend upon the alloy chemistry or the heat treatment condition, and play an important role in improving the mechanical properties of the alloys. In this study, the morphology and crystallographic characteristics of the titanium silicides in the Ti-Fe-Si alloy system were studied. Three types of silicides were found in the alloys; (1) interconnected chain-like silicides at grain boundary, (2) coarse silicides over im, (3) fine silicides smaller than 0.2m. Ti3Si was dominant in cast + HIP condition while Ti5Si3 was dominant in as-cast state. It is recognized that $Ti_5Si_3$$\rightarrow$$Ti_3Si$ transition occurred by the peritectoid reaction and it may be promoted by the pressure during HIP. However, in the case of the fine silicides, $Ti_3Si$ and $Ti_5Si_3$ were found simultaneously even after HIP. Such a fine silicide was found to have a crystallographic orientation relationship with matrix.

• Transactions on Electrical and Electronic Materials
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• v.12 no.6
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• pp.258-261
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• 2011

A ferroelectric $(Bi,La)_4Ti_3O_{12}$ (BLT) thin film fabricated by the pulsed-DC sputtering method was evaluated on a cell structure to check its compatibility to high density ferroelectric random access memory (FeRAM) devices. The BLT composition in the sputtering target was $Bi_{4.8}La_{1.0}Ti_{3.0}O_{12}$. Firstly, a BLT film was deposited on a buried Pt/$IrO_x$/Ir bottom electrode stack with W-plug connected to the transistor in a lower place. Then, the film was finally crystallized at $700^{\circ}C$ for 30 seconds in oxygen ambient. The annealed BLT layer was found to have randomly oriented and small ellipsoidal-shaped grains (long direction: ~100 nm, short direction: ~20 nm). The small and uniform-sized grains with random orientations were considered to be suitable for high density FeRAM devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.965-968
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• 2007

In this study we investigated the variation of the substrate temperatures using RF sputtering to identify the effect on the structure and electrical properties by c-axis orientation of ZnO thin film. ZnO thin films were prepared on Al/Si substrate. In our experimental results, ZnO thin film at $300^{\circ}C$ was well grown with (002) peak of ZnO thin film, the thin film showed the high resistivity with the value of $5.9{\times}10^7\;{\Omega}cm$ and the roughness with 27.06 nm. As increased the substrate temperatures, the grain size of ZnO thin films was increased. From these results, we could confirm the suitable substrate temperature of ZnO thin films for FBAR(film bulk acoustic resonator).

• Journal of the Korean Vacuum Society
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• v.8 no.3A
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• pp.231-237
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• 1999

$SrBi_{22.4}Ta_2O_9$ (SBT) thin films of 70~150 nm thickness were prepared on platinized silicon substrates by Liquid Source Misted Chemical Deposition (LSMCD) process, and their microstructure, feroelectric and leakage current characteristics were investigated. By annealing at $800^{\circ}C$ for 1 hour in oxygen ambient, SBT films were fully crystallized to the Bi layered perovskite structure without preferred orientation. The grain size of the LSMCD- derived SBT films was about 100nm, and was not varied with the film thickness. $2P_r$ and $E_c$ of the SBT films increased with decreasing the film thickness, and the 70nm-thick SBT film exhibited $2P_r$ of 17.8 $\mu$C/$\textrm{cm}^2$ and $E_c$ of 74kV/cm at applied voltage of 5V. Within the film thickness range of 70~150nm, the relative dielectric permittivity of the LSMCD-derived SBT film decreased with decreasing the film thickness. Leakage current densities lower than $10^{-7}\textrm{A/cm}^2$ at 5V were observed in the SBT films thicker than 125nm.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.146-154
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• 2010

The effects of severe plastic deformation, equal channel angular pressing, and annealing of Al 5052 alloy on elastic modulus have been studied. The AI 5052 alloy was plastically deformed by ECAP method after solution treatment, and then finally annealing heat treated. Elastic modulus was measured by conventional tensile and nano-indentation test, and also measured on the surface of the specimen using acoustic material signature of the acoustic microscope. The variation in the elastic modulus influenced by plastic deformation and heat treatment, inaccessible by the conventional techniques, was successfully measured by acoustic material signature and obtained the elastic modulus depending on crystal orientation at each grain.

• Journal of the Korean Society for Heat Treatment
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• v.18 no.4
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• pp.229-234
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• 2005

Effect of incident ion beam energy on microstructure and adhesion behavior of TiN thin films were studied. Without ion beam assist, TiN film showed (111) growth mode which was thought to have the lowest deformation energy. As the ion beam assist energy increased, TiN film growth mode was changed from (111) to (200) mode. On the Si(100) substrate the critical incident energy for growth mode change was 100 eV/atom, however the critical assist energy was 121 eV/atom on the STD61 substrate. Grain size of TiN films increased with the assist ion beam energy. Finally, adhesion strength of TiN films bombarded above the critical ion assist energy showed 4~5 times higher values than that with lower bombard ion energy.

• Journal of Surface Science and Engineering
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• v.39 no.1
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• pp.13-17
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• 2006

The effects of an organic additive, naphthalene trisulfonic acid (NTSA), contained in the nickel sulfamate bath on the surface properties of the electrodeposited nickel layer were investigated through electrochemical technique, x-ray diffraction analysis, and microscopic observation. The addition of NTSA facilitated the oxidation process of electrodeposited nickel layer during anodic scan and also increased the hardness and internal stress of the nickel film as the applied current density became higher. It seems that NTSA modulated the deposit structure during electrodeposition and so induced higher distribution of (110) orientation with respect to (200). With the increase of the NTSA in the bath, nickel layer was formed in small grain size, which resulted in enhanced surface evenness and brightness.

• Journal of Surface Science and Engineering
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• v.52 no.2
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• pp.78-83
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• 2019

Chloride baths for electrodeposited Ni thin films were fabricated by dissolving metal Ni powders with the mixed solution consisting of HCl and de-ionized water. Current efficiency, residual stress, surface morphology and microstructure of Ni films with the change of metal ion ($Ni^{2+}$) concentrations in the plating solution were studied. Current efficiency was measured to be more than 90% with increasing $Ni^{2+}$ concentrations in the plating solution. Residual stress of Ni thin film was increased from about 400 to 780 MPa with increasing $Ni^{2+}$ concentration from 0.2 to 0.5 M. It is gradually decreased to 650 MPa at 0.9 M $Ni^{2+}$ concentration. Smooth surface morphologies were observed over 0.3 M $Ni^{2+}$ concentration, but nodule surface morphology at 0.2 M. Ni films consist of FCC(111), FCC(200), FCC(220) and FCC(311) peaks in XRD patterns. Preferred orientation of FCC(111) was observed and its intensity was slightly decreased with increasing $Ni^{2+}$ concentration. The average grain size was slightly increased at 0.3 M $Ni^{2+}$ concentration and then slightly decreased with increasing $Ni^{2+}$ concentration.

• Journal of Surface Science and Engineering
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• v.54 no.1
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• pp.18-24
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• 2021

KNN is widely used in the electronic industry such as memory devices, sensors, and capacitors due to various structural, electrical, and eco-friendly properties. In this study, Mn-doped KNN was prepared by adopting a sol-gel method with advantages of low cost and large area thin film fabrication. The Mn-doped KNN thin films were deposited by annealing in air for 1 hour and 700℃. The surface morphology characteristics and grain size of the heat-treated KNN were observed by SEM and AFM, and we used the X-ray diffraction for measuring the crystal phase of KNN. The XRD analysis results show that the fabrication of (K0.5Na0.5)(Nb1-xMnn)O3 thin films by sol-gel method in the thin film process of this experiment was stable in the perovskite phase of c-axis orientation. The SEM and AFM results show that the cracks were not confirmed from the fracture surface data of KNN thin films and were densely deposited with thin films with uniform thickness.