• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.845-847
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• 1999

(Ba, Sr)$TiO_3$[BST] thin films were fabricated on Pt/$TiO_2/SiO_2$/Si substrate by RF sputtering. The structural and dielectric properties of the BST thin films were investigated with the deposition time. Increasing the deposition time from 20 min. to 60 min., second phases were decreased, and EST (111), (100), (200) peaks were increased. The relative dielectric constant and dielectric loss of the EST thin films with the thickness of 3000$\AA$ were 300 and 0.018, respectively at 1[kHz]. The relative dielectric constants was decreased and dielectric losses was increased as increasing the frequency.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.173-174
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• 2008

페로브스카이트 구조의 (Ba,Sr,Ca)$TiO_3$ 분말에 $Dy_2O_3$ 불순물을 첨가하여 첨가량에 따른 영향을 연구하였다. 시편의 제작은 Screen-printing을 이용하여 후막으로 제작하였으며, 구조적인 특성과 전기적인 특성을 관찰하였다. XRD 회절 분석을 통하여 $Dy_2O_3$가 첨가된 모든 시편에서 이차상이 없는 전형적인 페로브스카이트 구조를 나타내었다. 시편의 미세구조를 관찰한 결과 grain size는 $Dy_2O_3$ 첨가량이 증가 할수록 감소하였으며, 기공은 증가하는 것을 알 수 있었다. 후막의 두께는 $Dy_2O_3$ 첨가량에 영향을 받지 않았으며 평균 두께는 $69{\mu}m$이었다. 큐리 온도는 $Dy_2O_3$ 첨가량에 따라 감소하였으며, 유전 손실은 상온 이상에서 1%이하로 크게 감소하였다.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1353-1354
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• 2006

The dielectric properties of $Ba_{0.5}Sr_{0.5}TiO_3$(BST) and MgO-doped BST ceramics were investigated for tunable microwave applications by sol-gel method. The effects of MgO mixing with BST. It is observed that Mg substitution into BST causes a shift in the cubic-tetragonal BST Phase transition peak to a lower temperature. MgO-substituted BST and MgO-mixed phases exhibit homogeneous and broadened BST phase transition peaks. Mg substitution into BST has a significant effect on the grain sife reduction. Dielectric constant and loss is inhanced with decrease MgO dopant.

• Journal of the Korean Ceramic Society
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• v.43 no.11 s.294
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• pp.743-745
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• 2006

The luminescence properties of $Sr_{1-x}Ba_xTiO_3:Pr$, Al red phosphor for Field Emission Displays (FEDs) have been investigated in powders prepared though solid-state reactions. $Sr_{1-x}Ba_xTiO_3:Pr$, Al red phosphors indicate a higher luminescent intensity, and have been found to have potential for field emission displays. The addition of Ba increased the luminescence intensity at 617 nm by up to 30%. Ba ions are effective in producing the energy transfers from host-to-activator in 4f-5d transitions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.243-246
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• 1998

(Ba, Sr)TiO$_3$[BST] thin films were fabricated on Pt/SiO$_2$/Si substrate by RF sputtering technique. The structural, dielectric and electrical properties of BST thin films were investigated with Ar/O$_2$ ratio. Dielectric constant and dielectric loss of the BST thin film were about 1020 and 2.0[%], respectively. (at RF power 80W, post annealing temperature $650^{\circ}C$, deposition pressure of 5mTorr and Ar/O$_2$=80/20). For the BST(Ar/O$_2$=80/20) thin film with Polarization switching cycles of 10$^{10}$ , remanent polarization and coercive field were 0.084[$\mu$C/cm$^2$], 1.954[kV/cm], respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.5
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• pp.231-237
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• 2001

Etch rates up to 120 nm/min for $Ta_{2}O_{5}$ were achieved in both $SF_{6}/Ar$ and $Cl_{2}/Ar$ discharges. The effect of ultraviolet (UV) light illumination during ICP etching on $Ta_{2}O_{5}$ etch rate in those plasma chemistries was examined and UV illumination was found to produce significant enhancements in $Ta_{2}O_{5}$ etch rates most likely due to photoassisted desorption of the etch products. The effects of ion flux, ion energy, and plasma composition on (Ba, Sr)$TiO_3$ etch rate were examined and maximum etch rate ~90 nm/min was achieved in $Cl_{2}/Ar$ ICP discharges while $CH_{4}/H_{2}/Ar$ chemistry produced extremely low etch rates (${\leq}10\;nm/min$) under all conditions.

• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.198-205
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• 2003

$Ba_{0.66}Sr_{0.34}TiO_3$ thin films and seed-layers were deposited on $Pt/Ti/SiO_2/Si$substrate by R.F. magnetron sputtering method. Effects of various substrate temperature conditions on electrical properties (such as capacitance and leakage current) of BST thin films were studied. The effect of seed-layer was also studied. When seed-layer was inserted between BST and Pt, the crystallization of the BST thin films was considerably improved and the processing temperature was lowered. Compared to the pure BST thin films, dielectric constant, dielectric loss, and leakage current of BST thin films deposited on the seed-layer were considerably improved. It could be revealed that electrical properties are influenced by the substrate temperatures of BST thin films and are enhanced by the seed-layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.5.2-8
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• 1995

0.15($Ba_{1-x}Sr_{x}$)O-$0.15Sm_2O_3$-$0.7TiO_2$(x=0∼9[m/o]ceramics were fabricated by mixed-oxide method. Microwave dielectric properties were investigated with sintering conditions aid Sr addictive. In the specimen with x=0[m/o] sintered at 1350∼1470[$^{\circ}C$], dielectric constant, quality factor and temperature coefficient of resonant frequency were 70∼74, 2800∼3300(at 3[GHz]), -1.33∼+l.66[ppm/$^{\circ}C$, respectively. Increasing the Sr additive from 0 to 5[m/o], dielectric constant and temperature coefficient of resonant frequency were increased and quality factor was decreased. In the specimen with x=r[m/o] sintered at 1375[$^{\circ}C$], 6[hr], dielectric constant, quality factor and temperature coefficient resonant frequency were 75.62, 2785(at 3[GHz]), +8.39[ppm/$^{\circ}C$], respectively.

• Journal of the Korean Vacuum Society
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• v.11 no.3
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• pp.166-170
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• 2002

Artificial $BaTiO_3$(BTO)/$SrTiO_3$(STO) oxide superlattice have been deposited on MgO (100) single crystal substrate by pulsed laser deposition(PLD) method. The stacking periodicity of BTO/STO superlattice structure was varied from $BTO_{1\;unit\; cell}/STO_{1\;unit\; cell}$ to $BTO_{125\;unit\; cell}/STO_{125 \;unit \;cell}$ thickness with the total thickness of 100 nm. The result of X-ray diffraction showed the characteristics of superlattice in the BTO/STO multilayer structure. we have also confirmed that there was no interdiffusion at the interface between BTO and STO layers by high resolution transmission electron microscopy(HRTEM). The dielectric constant of superlattice increased with decreasing stacking periodicity of the BTO/STO superlattice within the critical thickness. The dielectric constant of the BTO/STO superlattice reached a maximum i.e., 1230 at a stacking perioicity of $BTO_{2\;unit\; cell}/STO_{2\;unit\; cell}$ .

• Proceedings of the Materials Research Society of Korea Conference
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• 2002.05a
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• pp.60-60
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• 2002