• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.131-131
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• 2000

We witnessed the enhancement of mangetoresistance (MR) in La0.75Ca0.25MnO3 thin films grown on Si (100) substrates by RF magnetron sputtering. The films are polycrystalline with (100) and (110) orientations. The lattice constants of films are reduced as much as 0.9% compared to the one of the bulk sample, which proves that the compressive stress on films was imposed by Si sbustrate. It is found that the MR value (Δ$\rho$/$\rho$0) of films are 0.33, 0.29 and 0.27 under a magnetic field of 1.5T for each films with deposition temperature of $700^{\circ}C$, 75$0^{\circ}C$ and 80$0^{\circ}C$, respectively. The correlation between the MR values and lattice constants of films is discussed. It is concluded that the compressive stress on films cause the enhancement of MR values of thin films grown on Si (1000 substrates. Some mechanism of compressive stress induced by Si substrate is suggested.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.4
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• pp.35-39
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• 1999

The $Li_2O-MgO-MgF_2-SiO_2$glasses with addition of $B_2O_3$ were investigated in order to make glass-ceramics for low temperature firing substrate. Glasses were made by melting at $1450^{\circ}C$ in the electronic furnace and crystallized at $750^{\circ}C$. The crystal phases were polycrystalline of lithium boron fluorphlogopite and lithium fluorhectorite. The crystal shape was chanced to granule type from needle type with increasing $B_2O_3$ content. Average particle size of the glass-ceramics after water swelling was 3.77$\mu\textrm{m}$. The optimum sintering temperature and sintering shrinkage of the substrate were $900^{\circ}C$ and 13.4%, respectively.

• Journal of the Korean Ceramic Society
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• v.44 no.8
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• pp.403-406
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• 2007

Ferroelectric Ce-doped $Bi_4Ti_3O_{12}$ (BCT) thin films were deposited by liquid delivery metal organic chemical vapor deposition (MOCVD) onto a $Pt(111)/Ti/SiO_2/Si(100)$ substrate. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to identify the crystal structure, the surface, and the cross-section morphology of the deposited ferroelectric flims. After annealing above $640^{\circ}C$, the BCT films exhibited a polycrystalline structure with preferred (001) and (117) orientations. The BCT lam capacitor with a top Pt electrode showed a large remnant polarization ($2P_r$) of $44.56{\mu}C/cm^2$ at an applied voltage of 5 V and exhibited fatigue-free behavior up to $1.0{\times}10^{11}$ switching cycles at a frequency of 1 MHz. This study clearly reveals that BCT thin film has potential for application in non-volatile ferroelectric random access memories and dynamic random access memories.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.3
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• pp.238-244
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• 1994

We investigated solution growth of silicon on borosilicate and quartz glass substrates in the temperature range of $800^{\circ}C~520^{\circ}C$. A thin Al-Si layer evaporated onto the substrate serves to improve the wetting between the substrate and the Al/Ga solvent. Nucleation takes place by a reaction of Al with $SiO_2$ from the substrate. We obtained silicon deposits with a grain size up to a few 100 $\mu\textrm{m}$. There was a perferential (111) orientation for the case of quartz glass substrates while there is a strong contribution of other orientations for the deposition of Si on borosilicate glass substrates.

• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.130-137
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• 2008

$La_{0.7}Sr_{0.3}MnO_3$ films were deposited on $SiO_2$/Si and Si substrates annealed at $350^{\circ}C$ by rf magnetron sputtering. The oxygen gas flow rates were varied as 0, 40, and 80 sccm. Without post annealing process, $La_{0.7}Sr_{0.3}MnO_3$ thin films on $SiO_2$/Si and Si substrates were polycrystalline with (100), (110), and (200) growth planes. The grain size of $La_{0.7}Sr_{0.3}MnO_3$ thin films was increased with increasing oxygen gas flow rate. The sheet resistance of $La_{0.7}Sr_{0.3}MnO_3$ thin films was decreased with oxygen flow rate due to the increased grain size which induced a reduction of grain boundary. TCR (temperature coefficient of resistance) values of $La_{0.7}Sr_{0.3}MnO_3$ thin films were obtained from -2.0% to -2.2%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.486-491
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• 2002

We have fabricated $Bi_{3.25}La_{0.75}Ti_3O_12$ (BLT) thin films on the Pt/Ti/$SiO_2$/Si substrates using a metalorganic decomposition (MOD) method with annealing temperature from $550^{\circ}C$ to $750^{\circ}C$. The structural properties of BLT films examined by x-ray diffraction (XRD). From XRD analysis. BLT thin films show polycrystalline structure. The layered-perovskite phase was obtained by spin-on films at above $600^{\circ}C$ for 1h. Scanning electron microscopy (SEM) showed uniform surface composed of rodlike grains. The grain size of BLT films increased with increasing annealing temperature. The BLT film annealed at $650^{\circ}C$ was measured to have a dielectric constant of 279, dielectric loss of 1.85(%), remanent polarization of $25.66\mu C/\textrm{cm}^2$, and coercive field of 84.75 kV/cm. The BLT thin films showed little polarization fatigue test up to $3.5{\times}10^9$ bipolar cycling at 5 V and 100 kHz.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1296-1299
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• 2012

$YBa_2Cu_3O_{7-x}$ thin films were fabricated by the spin-coating method on $SiO_2$/Si substrate using an alkoxide-based sol-gel method. The structural and electrical properties were investigated for various 1st annealing temperature. Due to the formation of the polycrystalline single phase, synthesis temperature was observed at around $720^{\circ}C-800^{\circ}C$. $YBa_2Cu_3O_{7-x}$ thin films with the 1st annealing temperature of $450^{\circ}C{\sim}500^{\circ}C$ showed the single XRD patterns without the second phase, such as $YBa_2Cu_4O_8$. The thickness of films was approximately $0.23{\mu}m{\sim}0.27{\mu}m$. Aerage grain size, resistance and temperature coefficient of resistance (TCR) of $YBa_2Cu_3O_{7-x}$ thin films with the 1st annealing temperature of $500^{\circ}C$ were $0.27{\mu}m$, $59.7M{\Omega}$ and -3.7 %/K, respecvitely.

• Transactions on Electrical and Electronic Materials
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• v.1 no.1
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• pp.22-25
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• 2000

Polycrystalline SBTN layered ferroelectric thin film with various Nb mole ratios were prepared by sol-gel method Pt/ $SiO_2$/Si (100) substrates. The films were annealed at different temperature and characterized in terms of phase and microstructure. The films were crystallized with a high (105) diffraction intensity and had rodike structure, SBTN films fired at 800$^{circ}C$ revealed standard hysteresis loops with no fatigue for up to 10$^{10}$ cycles. At an applied voltage of 5V the dielectric constant($varepsilon$) , dissipation factor (tan $delta$), remanent polarization(ZPr) and coercive field(Ec) of typical S $r_{0.8}$B $i_{2.3}$(T $a_{1-x}$ N $b_{x}$) $O_{9+}$$alpha$/ thin film(x=0.1) prepared on Pt/ $SiO_2$/Si (100) were about 277.7, 0.042, 3.74$mu$C/$textrm{cm}^2$, and 24.8kv/cm respectively.ly.y. respectively.ly.y.y..

• Current Photovoltaic Research
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• v.1 no.2
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• pp.103-108
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• 2013

Epitaxial growth of a high-quality thin Si film is essential for the application to low-cost thin-film Si solar cells. A polycrystalline Si film was grown on a $SiO_2$ substrate at $450^{\circ}C$ by a Al-assisted crystal growth process. For the purpose, a thin Al layer was deposited on the $SiO_2$ substrate for Al-assisted crystal growth. However, the epitaxial growth of Si film resulted in a rough surface with humps. Then, we introduced a thin amorphous Si seed layer on the Al film to minimize the initial roughness of Si film. With the help of the Si seed layer, the surface of the epitaxial Si film was smooth and the crystallinity of the Si film was much improved. The grain size of the $1.5-{\mu}m$-thick Si film was as large as 1 mm. The Al content in the Si film was 3.7% and the hole concentration was estimated to be $3{\times}10^{17}/cm^3$, which was one order of magnitude higher than desirable value for Si base layer. The results suggest that Al-doped Si layer could be use as a seed layer for additional epitaxial growth of intrinsic or boron-doped Si layer because the Al-doped Si layer has large grains.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.244-247
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• 1999

The(Sr$\sub$0.85/Ca$\sub$0.15/) TiO$_3$(SCT) thin films are deposited on Pt-coated electrode(Pt/TiN/SiO$_2$/Si) using RF sputtering method. The composition of SCT thin films deposited on Si substrate at room temperature is close to stoichiometry(1.102 in A/B ratio). Also, SCT thin films deposited on Pt-coated electrodes have the cubic perovskite structure and polycrystalline state. The maximum dielectric constant of SCT thin films is obtained by annealing at 600[$^{\circ}C$].The dielectric constant changes almost linearly in temperature ranges of -80~+90[$^{\circ}C$].