• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.10
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• pp.59-66
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• 1993

PZT thin film deposited by rf magnetron sputtering was annealed by rapid thermal process(RTP) in PbO ambient to prevent vaporing of Pb and interface reactions. Si and TiN/Ti/Si substrates were prepared to survey application of TiN/Ti layer which can prevent interface interaction with Si and crack of PZT thin films. As temperature increased. PZT thin films surface on Si substrate appeared more severe cracks which should affect electrical properties deadly. TiN/Ti(40-150${\mu}{\Omega}{\cdot}cm$) layer applied for buffer layer suppressed interface interaction and film cracking. The measured leakage current(LC) and breakdown voltage(BV) of PZT thin film on TiN/Ti/Si substrate annealed at 650$^{\circ}$C for 15 sec (thickness of 2500$\AA$) were 38 nA/cm2 and 3.5 MV/cm and dielectric constant was 310 at 1 MHz, and remanent polarization (Pr) and coercive field (Ec) were 6.4${\mu}C/cm^{2}$ and 0.2MV/cm at 60 Hz, respectively.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.2
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• pp.46-53
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• 2000

Hot forging of aluminum alloy has the bad machinability due to continuous chip formation caused from the ductility The bad machinability requires a labor and a high cost to produce final products after hot forging. In industrial field, T4 heat treatment is performed to improve the machinability, and the annealing and the cold sizing are followed. In this study, a series of heat treatments are introduced during hot forging operation without T4 heat treatment after forming so that it improves the machinability with reduction of the number of operations and machining cost. Instead of T4 heat treatment, water cooling and air cooling are tried and compared to find out an optimum cooling condition

• Korean Journal of Materials Research
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• v.16 no.9
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• pp.571-577
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• 2006

We fabricated thermal evaporated 10 nm-Ni/(poly)Si and 10 nm-Ni/1 nm-Ir/(poly)Si films to investigate the thermal stability of nickel monosilicide at the elevated temperatures by rapid annealing them at the temperatures of $300{\sim}1200^{\circ}C$ for 40 seconds. Silicides for salicide process was formed on top of both the single crystal silicon actives and the polycrystalline silicon gates. A four-point tester is used for sheet resistance. Scanning electron microscope and field ion beam were employed for thickness and microstructure evolution characterization. An x-ray diffractometer and an auger depth profile scope were used for phase and composition analysis, respectively. Nickel silicides with iridium on single crystal silicon actives and polycrystalline silicon gates showed low resistance up to $1200^{\circ}C$ and $800^{\circ}C$, respectively, while the conventional nickel monosilicide showed low resistance below $700^{\circ}C$. The grain boundary diffusion and agglomeration of silicides led to lower the NiSi stable temperature with polycrystalline silicon substrates. Our result implies that our newly proposed Ir added NiSi process may widen the thermal process window for nano CMOS process.

• Journal of the Korean Ceramic Society
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• v.30 no.6
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• pp.510-516
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• 1993

$PbTiO_3$ thin films have been formed by rapid thermal annealing(RTA) of $TiO_2$/Pb/$TiO_2$ multilayer films deposited on Si wafers by RF sputtering. Based on the optimal depositon conditions of TiO2 and Pb, $TiO_2$/Pb/$TiO_2$ three layers were deposited for 900$\AA$ each. These films were subjected to RTA process at the temperatures ranging from $400^{\circ}C$ to $900^{\circ}C$ for 30 seconds in air, and were analyzed by X-ray diffraction and transmission electron microscopy to investigate the phases and the microstructures. As a result, perovskite $PbTiO_3$ phases was obtained above $500^{\circ}C$ with the trace of unreacted $TiO_2$. RBS analysis revealed the anisotropic behavior of diffusion that the diffusivity of Pb to the bottom $TiO_2$ layer was faster than that of Pb to the top $TiO_2$ layer. The amorphous Pb-silicate was formed between film and Si substrate due to the diffusion of Pb, but Pb-silicate existed locally at the interface and the amount of that phase was very small. Therefore the effect of bottom $TiO_2$ layer as a diffusion barrier was confirmed. $PbTiO_3$ films formed by current technique showed a relative dielectric constant of 60, and the maximum breakdown field reached 170kV/cm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.326-329
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• 2002

In this paper, we investigated a feasibility of cerium oxide(CeO$_2$) films as a buffer layer of MFIS(metal ferroelectric insulator semiconductor) type capacitor. CeO$_2$ layer were Prepared by two step process of a low temperature film growth and subsequent RTA (rapid thermal annealing) treatment. By app1ying an ultra thin Ce metal seed layer and N$_2$ Plasma treatment, dielectric and interface properties were improved. It means that unwanted SiO$_2$ layer generation was successfully suppressed at the interface between He buffer layer and Si substrate. The lowest lattice mismatch of CeO$_2$ film was as low as 1.76% and average surface roughness was less than 0.7 m. The Al/CeO$_2$/Si structure shows breakdown electric field of 1.2 MV/cm, dielectric constant of more than 15.1 and interface state densities as low as 1.84${\times}$10$\^$11/ cm$\^$-1/eV$\^$-1/. After N$_2$ plasma treatment, the leakage current was reduced with about 2-order.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.539-542
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• 2004

The $ZnGa_2O_4$ phosphor target is synthesized through solid-state reactions at the calcine temperature of $700^{\circ}C$ and sintering temperature of $1300^{\circ}C$ in order to deposit $ZnGa_2O_4$ phosphor thin film by rf magnetron sputtering system. The $ZnGa_2O_4$ phosphor thin film is deposited on Si(100) substrate and prepared $ZnGa_2O_4$ phosphor thin film is annealed by rapid thermal processor(RTP) at $700^{\circ}C$, 15sec. The x-ray diffraction patterns of $ZnGa_2O_4$ phosphor target and thin film show the position of (311) main peak. The cathodoluminescenre(CL) spectrums of $ZnGa_2O_4$ phosphor thin film show main peak of 420nm and maximum intensity at the substrate temperature of $500^{\circ}C$ and annealing temperature of $700^{\circ}C$ 15sec.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.200-200
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• 2008

This paper reports on electrical characterization by IDC pattern using BST$(Ba_{0.5}Sr_{0.5}TiO_3)$ thin film. BST thin films have been deposited on $Al_2O_3$ Substrates by Nd-YAG pulsed laser deposition with a 355nm wavelength at $700^{\circ}C$. The post deposition annealing at $750^{\circ}C$ in flowing $O_2$ atmosphere for I hours. The capacitance of IDC patterns have been measured from 1 to 10 GHz as a function fo electric field (${\pm}40$ KV/cm) at room temperature using interdiigitated Au electrodes deposited on top of BST. The IDC patterns have three type of fingers number. For the finger paris was increased onto $Al_2O_3$, the capacitance increased. The capacitance of 5 pairs finger was 0.3pF and 10 pairs finger was 0.9pF.

• Toxicological Research
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• v.26 no.1
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• pp.15-19
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• 2010

Mesenchymal stem cells (MSCs) have greater potential for immediate clinical and toxicological applications, due to their ability to self-renew, proliferate, and differentiate into a variety of cell types. To identify novel candidate genes that were specifically expressed during transdifferentiation of human MSCs to neuronal cells, we performed a differential expression analysis with random priming approach using annealing control primer-based differential display reverse transcription-polymerase chain reaction approach. We identified genes for acyl-CoA thioesterase, tissue inhibitor of metalloproteinases-1, brain glycogen phosphorylase, ubiquitin C-terminal hydrolase and aldehyde reductase were up-regualted, whereas genes for transgelin and heparan sulfate proteoglycan were down-regulated in MSC-derived neurons. These differentially expressed genes may have potential role in regulation of neurogenesis. This study could be applied to environmental toxicology in the field of testing the toxicity of a chemical or a physical agent.

• Journal of IKEEE
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• v.24 no.2
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• pp.435-440
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• 2020

ZnO:Al films with about 500 nm thick were prepared by RF magnetron sputtering. The ZnO:Al films were annealed at 100 ℃, 200 ℃, 300 ℃, and 400 ℃ for 10 h, respectively. The resistivity, carrier concentration, and mobility variation of ZnO:Al films with heat treatments were measured. The causes of the resistivity variation of ZnO:Al films with heat treatments were investigated by utilizing the results of x-ray diffraction and field emission scanning electron microscope. The energy band gap, Urbach energy, and refractive index were obtained from the transmittance of ZnO:Al films. The change in electrical properties of the ZnO:Al film was explained in relation to the optical properties.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.195-198
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• 1999

A Bi$_4$Ti$_3$O$_{12}$ (BIT) thin film is prepared by sol-gel method using acetate precursors and evaluated whether it could be applied to NVFRAM. The drying and the annealing temperature are 40$0^{\circ}C$ and $650^{\circ}C$, respectively and they are determined from the DT-TG analysis. The BIT thin film deposited on Pt/Ta/SiO$_2$/Si substrate shows orthorhombic perovskite phase. The grain size and the surface roughness are about 100 nm and 70.2$\AA$, respectively. The dielectric constant and the loss tangent at 10 KHz are 176 and 0.038, respectively, and the leakage current density at 100㎸/cm is 4.71$mutextrm{A}$/$\textrm{cm}^2$. In the results of hysteresis loops measured at $\pm$250㎸/cm, the remanent polarization (Pr) and the coercive field (Ec) are 5.92$mutextrm{A}$/$\textrm{cm}^2$ and 86.3㎸/cm, respectively. After applying 10$^{9}$ square pulses of $\pm$5V, the remanent polarization of the BIT thin film decreases as much as about 33% from 5.92 $\mu$C/$\textrm{cm}^2$ of initial state to 3.95 $\mu$C/$\textrm{cm}^2$.