• Journal of the Korean Ceramic Society
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• v.28 no.3
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• pp.215-224
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• 1991

The synthesis of SrTiO3 powders having high purity and homogeneous submicron particle size was attempted by the oxalate method. The microstructure and dielectric properties of SrTiO3 based boundary layer capacitor (BLC) were investigated. Strontium titanyl oxalate[SrTiO(C2O4)2.4H2O] was prepared from the mixing solution of (Sr, Ti) using oxalic acid(H2C2O4) as a precipitating agent at 8$0^{\circ}C$. The crystalline SrTiO3 powder was obtained by thermal decomposition of the precipitate above $600^{\circ}C$. The crystalline SrTiO3 powder containing Nb2O5 as a dopant, TiO2 and SiO2 as additives was sintered at 1360~144$0^{\circ}C$ in the reducing atmosphere to get semiconductive SrTiO3. Insulating material containing PbO-Bi2O3-B2O3 frit was printed on the sintered semiconductive SrTiO3 and fired at 120$0^{\circ}C$ for 2h to get the grain boundary diffusion.

• Journal of the Korean Ceramic Society
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• v.46 no.5
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• pp.467-471
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• 2009

Effects of boron and carbon on the densification and thermal decomposition of an AlN-SiC-$TiB_2$ system were investigated. $SiO_2$ was mostly removed by the addition of carbon, while $Al_2O_3$ formed $Al_4O_4C$ and promoted the densification of the systems above $1850^{\circ}C$. Rather porous specimens were obtained without the additives after hot pressing at $2100^{\circ}C$, while densification was mostly completed at $2000^{\circ}C$ by using the additives. The sintering temperature decreased further to $1950^{\circ}C$ by applying spark plasma sintering. The additives promoted the shrinkage of AlN by forming a liquid phase which was originated from the carbo- and boro-thermal reduction of $Al_2O_3$ and AlN.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.36-43
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• 1997

FECAPS(ferroelectric capacitors) have been fabricated by RF magnetron sputtering deposition of 3000$\AA$ PZT thin films on the Pt/Ti/$SiO_2$/Si substrates and post-annealing with the temperature of $550^{\circ}C$~$650^{\circ}C$ for 10 sec~50 sec in a RTA system. The electrical characteristics of the fabricated capacitors showed the highest dielectric constant and remanent polarization[${\varepsilon_r(1kHz)$=690, $2P_r$(-5V~5V sweep)=22$\mu$C/$ \textrm{cm}^2$] in the samples annealed at $650^{\circ}C$ for 30 sec, while the lowest tangent loss and leakage current [$tan\delta(\ge10kHz)\le0.02, \; J_i(5V)=3\mu\textrm{A}/\textrm{cm}^2$]in the samples annealed at $600^{\circ}C$ for 30 sec.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1236-1238
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• 1997

유전체 PLT(28) ($Pb_{0.72}La_{0.28}Ti_{0.93}O_3$) 박막을 레이저 어블레이션 기법으로 Pt/Ti/$SiO_3$/Si기판을 $500^{\circ}C{\sim}700^{\circ}C$까지 가열한 상태에서 $O_2$분위기에서 증착시켰다. 증착된 박막은 SEM, XRD 등의 구조적 분석을 통하여 $600^{\circ}C$이상에서 증착된 경우, (111)방향으로 우세하게 성장한, 결정성이 양호한 박막임을 확인하였다. 박막의 전기적 특성은, 증착 온도가 $650^{\circ}C$일 때 약 1400정도의 높은 비유전율을 얻었으며, 전하저장밀도는 100[KV/cm]에서 약 9[${\mu}C/cm^2$]이었다.

• Journal of the Korean Vacuum Society
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• v.9 no.3
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• pp.249-253
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• 2000

We have analyzed electrical characteristics of the amorphous $MgTiO_3$thin films deposited by pulsed laser deposition (PLD) technique with the temperature of 400~$500^{\circ}C$. The electrical characteristics of $MgTiO_3$films heavily depend on the deposition temperature. We speculate that the density of anomalous positive charge (APC) substantially increases as the deposition temperature lowers, causing the HF C-V curves shift to the direction of the negative gate voltage. We further observed that both the degree of C-V shift as a function of the deposition temperature and the density of APC were minimized by the use of $SiO_2$with thickness of approximately 100 $\AA$ between $MgTiO_3$films and the Si substrate.

• Journal of the Korean Vacuum Society
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• v.11 no.4
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• pp.201-206
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• 2002

Pd/Si/Pd/Ti/Au ohmic contact to n-type InGaAs was investigated with rapid thermal annealing conditions. Minimum specific contact resistivity of $3.9\times10^{-7}\Omega\textrm{cm}^2$ was achieved at $400^{\circ}C$/20sec. This was related to the formation of Pd-Si compounds by rapid thermal annealing and the in-diffusion of Si atoms to InGaAs surface. However, the specific contact resistivity increased slightly to low-$10^{-6}\Omega \textrm{cm}^2$ at $400^{\circ}C$ for longer than 30 seconds, and to high-$10^{-7}$ at 425~$450^{\circ}C$ for 10 seconds. This resulted from the formation of Pd-Ga compounds. Superior ohmic contact and non-spiking planar interface between ohmic materials and InGaAs were maintained after annealing at high temperature. Therefore, this thermally stable ohmic contact system is a promising candidate for compound semiconductor devices.

• Korean Journal of Materials Research
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• v.5 no.7
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• pp.816-819
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• 1995

(Ba$_{1-x}$ , Sr$_{x}$)TiO/$_3$thin films on Pt/Ti/SiO$_2$/Si substrates were prepared by LP MOCVD(Low Pressure Metal-Organic Chemical Vapor Deposition). The crystalinity of BST deposit had a (100) preferred orientation with increasing deposition temperature due to surface diffusion. BST films deposited at 90$0^{\circ}C$ showed a dielectric constant of 365 and a dissipation factor of 0.052 at a frequency of 100kHz. The chance of capacitance of the films with applied voltage was small, showing paraelectric properties. BST film deposited at 90$0^{\circ}C$ had a charge storage density of 60 fc/${\mu}{\textrm}{m}$$^2$at a field of 0.2MV/cm and the leakage current density of 20 nA/$\textrm{cm}^2$ at a field of 0.15 MV/cm.cm.

• Journal of the Korean Ceramic Society
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• v.39 no.8
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• pp.742-749
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• 2002

The PZT thin films werre deposited on Pt/Ti/$SiO_2$/Si substrate by R. F. magnetron sputtering with $Pb_{1.1}Zr_{0.53}Ti_{0.47}O_3$ target. When interlayers(PbO, $TiO_2$, PbO/$TiO_2$) were inserted between PZT and Pt, the crystallization of the PZT thin films was considerably improved and the processing temperature was lowered. Compared to the pure PZT thin films, dielectric constant, dielectric loss and polarization properties of PZT thin films with interlayers were considerably improved. From XPS depth profile analysis, it was confirmed that PZT thin films and interlayers existed independently. In particular, PZT thin films deposited on interlayer(PbO/$TiO_2$) showed the best dielectric property (${\varepsilon}_r$=414.94, tan${\delta}$=0.0241, Pr=22${\mu}C/cm^2$).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.4
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• pp.178-183
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• 2002

The PLZT (x/50/50, x = 1, 2, 5, 7) thin films have been prepared by a sol-gel method using polypropanediol as a solvent, and their dielectric properties have been investigated. The prepared sol was coated 10 times on $Pt/Ti/SiO2_2$/Si wafer. After post-annealing at 560~$600^{\circ}C$ for 10 min, the 600 nm-thick PLZT (x/50/50) thin films were formed with pure perovskite phase. Grain size of the PLZT (x/50/50) thin films was increased with increasing the amount of La. For all the compositions, dielectric properties such as dielectric constant and remnant polarization were enhanced with increasing annealing temperatures. As the amount of La was increased, the remnant polarization, coercive field and dielectric constant of the PLZT (x/50/50) thin films fired at $600^{\circ}C$ were decreased.

• Proceedings of the KIEE Conference
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• 1999.11a
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• pp.31-34
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• 1999

In the present study, we fabricated stoichiometric $(Ba_{1-x}Sr_x)TiO_3$ thin films at various substrate temperature and contents using of magnetron sputtering method on optimized Pt-based electrodes (Pt/TiN/$SiO_2$/Si). The substate temperature deposited at 200[ $^{\circ}C$], 400[$^{\circ}C$] and 600[$^{\circ}C$] and crystalline BST thin films show above 400[$^{\circ}C$]. Also, the composition of $(Ba_{1-x}Sr_x)TiO_3$ thin films deposited on Si wafer substrate at 400[$^{\circ}C$] were closed to stoichiometry($1.015{\sim}1.093$ in A/B ratio), but compositional deviation from a stoichiometry is larger as $SrCO_3$ is added. The drastic decrease of dielectric constant and increase of dielectric loss in $(Ba_{1-x}Sr_x)TiO_3$thin films is observed above 100[kHz]. V-I characteristics of $(Ba_{1-x}Sr_x)TiO_3$ thin films show the decrease of leakage current with the increase of $SrCO_3$ contents.