• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.50-50
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• 1996

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.6
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• pp.454-457
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• 2010

The influence of CuO addition on what of the $(Ba,Sr)TiO_3$ ceramics was studied. The sintering temperature of $(Ba,Sr)TiO_3$ ceramics was lowered by the addition of CuO additives. The 1 - 5 wt% CuO were selected and employed as the sintering aids. Low-Temperature Co-fired Ceramic technologies are popular technologies used in the manufacture of microwave devices. In this study, crystalline and electrical properties of CuO doped $(Ba,Sr)TiO_3$ ceramics were investigated to determine the low temperature sintering properties. The addition of CuO to $(Ba,Sr)TiO_3$ lowered the sintering temperature from $1350^{\circ}C$ to $1150^{\circ}C$. The dependence of the sintering temperature shrinkage rate and mechanism of CuO doped $(Ba,Sr)TiO_3$ ceramics are investigated and discussed. Also, the crystalline structure of CuO - doped $(Ba,Sr)TiO_3$ ceramics is discussed by the X-ray diffraction (XRD) method.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.863-866
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• 1999

(Ba,Sr)$TiO_3$ thin films have attracted groat interest as new dielectric materials of capacitors for ultra-large-scale integrated dynamic random access memories (ULSI-DRAMs) such as 1 Gbit or 4 Gbit. In this study, inductively coupled $BCl_3/Cl_2$/Ar plasmas was used to etch (Ba,Sr)$TiO_3$ thin films. RF power/dc bias voltage = 600 W/-250 V and chamber pressure was 10 mTorr. The $Cl_2/(Cl_2+Ar)$ was fixed at 0.2, the (Ba,Sr)$TiO_3$ thin films were etched adding $BCl_3$. The highest (Ba,Sr)$TiO_3$ etch rate is 480$\AA/min$ at 10 % $BCl_3$ adding to $Cl_2$/Ar. The characteristics of the plasmas were estimated using optical emission spectroscopy (OES). The change of Cl, B radical density measured by OES as a function of $BCl_3$ percentage in $Cl_2$/Ar. The highest Cl radical density was shown at the addition of 10% $BCl_3$ to $Cl_2$/Ar. To study on the surface reaction of (Ba,Sr)$TiO_3$ thin films was investigated by XPS analysis. Ion enhancement etching is necessary to break Ba-O bond and to remove $BaCl_2$. There is a little chemical reaction between Sr and Cl, but Sr is removed by physical sputtering. There is a chemical reaction between Ti and Cl, and Tic14 is removed with ease. The cross-sectional of (Ba,Sr)$TiO_3$ thin film was investigated by scanning electron microscopy (SEM), the etch slope is about $65\;{\sim}\;70$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.9
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• pp.724-727
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• 2009

We have fabricated (Ba,Sr)TiO3$TiO_3$ thick films doped with various amount of ZnBO dopants (1, 3, and 5 wt%) by screen printing method on the alumina substrates, which were sintered at the temperature below $1200^{\circ}C$. With increasing the amount of ZnBO dopants, the relative dielectric permittivity of ZnBO doped (Ba,Sr)$TiO_3$ was decreased, while loss tangent was increased. 1 wt% ZnBO doped (Ba,Sr)$TiO_3$ thick film has relative dielectric permittivity of 759 at 1 MHz, while 3 and 5 wt% of ZnBO doped (Ba,Sr)$TiO_3$ thick films have 624 and 554, respectively. By introducing ZnBO dopants to the (Ba,Sr)$TiO_3$ thick films, leakage current densities were decreased. The decreased leakage current with increasing ZnBO dopants can be explained by increased density and grain size of thick film on alumina substrate. We believe this decreased leakage current density probably come from the increased grain size and increased density.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.525-530
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• 2011

We investigated the electrical properties the starting material and sintering condition on the laminated PTC thermistor for micro circuit protection. The influences of $BaTiO_3$ powder with the 0.3 and 0.45 ${\mu}m$ size and the electrical characteristics (Ba,Sr)$TiO_3$ sintered at 1350~1400$^{\circ}C$ for 2 h in a reducing atmosphere (1% $H_2/N_2$). The sintered (Ba,Sr)$TiO_3$ was increased pore and the grain size was decreased according to increasing Sr additions. In relative permittivity, the phase transition temperature of (Ba,Sr)$TiO_3$ was decreased for 2.5$^{\circ}C$ according to increasing 0.01 mole Sr additions, and the phase transition dose not appeared about 0.3 mole Sr addition. The (Ba,Sr)$TiO_3$ was show the low resistance from 0.01 mole to 0.05 mole by Sr addition, regardless of sintering temperature. The (Ba,Sr)$TiO_3$ was show $10^2$ jump order at 0.1 and 0.2 mole Sr addition, and PTCR of the sintered $(Ba_{0.7}Sr_{0.3})TiO_3$ does not appeared about 0.3 mole Sr addition, regardless of the sintering temperature and starting material size.

• Journal of the Korean Ceramic Society
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• v.30 no.6
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• pp.441-448
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• 1993

The Ba1-xSrxTiO3 thin films deposited on ITO-coated glass substrate at 55$0^{\circ}C$ by rf magnetron sputtering method have individual preferential orientations as a function of composition (X=0, 0.25, 0.5, 0.75, 1) due to the stress relief interactions among the intrinsic compressive stress, thermal tensile stress adn extrinsic compressive stress (compressive stress in case of BaTiO3(Tc=12$0^{\circ}C$) and Ba0.75Sr0.25TiO3(Tc=57$^{\circ}C$)). This behavior also appears on the (BaSr)TiO3 thin films (X=0.5) deposited on ITO-coated glass substrate at deposition temperature between 35$0^{\circ}C$ and 55$0^{\circ}C$. The composition of Ba1-xSrxTiO3 thin films deposited on ITO-coated glass substrate at 55$0^{\circ}C$ is close to stoichiometry (1.009~1.089 in A/B ratio), but the compositional deviation from a stoichiometry is larger as SrTiO3 is added. The morphology of Ba1-xSrxTiO3 thin films is very similar for over all substrate temperatures, and the roughness due to the differences of cluster size is the smallest at X=0.25.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1488-1490
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• 2002

The (Bi,Ba,Sr)$TiO_3$[BBST] thin films were fabricated on Pt/Ti/$SiO_2$/Si substrate by RF sputtering method. We investigated the effects of Ar/$O_2$ rates on the structural properties of BBST thin films. Decreasing the $O_2$ rates, the intensity of $BaBi_4Ti_4O_{15}$ and $Bi_4Ti_3O_{12}$ peaks were increased but the $(Ba_{0.5}Sr_{0.5})TiO_3$ peak was decreased. In the case of BBST thin films deposited with condition of 90/10 (Ar/$O_2$) ratio, the composition of Ba/Sr/Bi was 0.35/0.4/0.25. Also, in the BBST thin films deposited with condition of 80/20(Ar/$O_2$) ratio, the composition of Br,Sr and Ti were relatively uniform. But the component of Bi and Ti were diffused into the Pt layers.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.85-87
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• 2002

The $(Ba_xBi_{0.6-x}Sr_{0.4})TiO_3$[x=0.1, 0.2, 0.3] ceramics were prepared by conventional mixed oxide method The structural properties of the $(Ba_xBi_{0.6-x}Sr_{0.4})TiO_3$[x=0.1, 0.2, 0.3] ceramics with the sintering temperature($1200^{\circ}C,\;1250^{\circ}C,\;1300^{\circ}C$) were investigated by XRD, SEM, EDS. Increasing the sintering temperature, the intensity of the $Ba_{0.5}Sr_{0.5}TiO_3$ (100), (110), (111), (200), (310) peaks and $SrBi_4Ti_4O_{15}$ (319), (040) peaks were increased. The gram of the $(Bi_{0.2}Ba_{0.4}Sr_{0.4})TiO_3$ ceramics sintered at $1250^{\circ}C$ were fine and uniform. Increasing the sintering temperature. the average gram size of the $(Bi_{0.2}Ba_{0.4}Sr_{0.4})TiO_3$ ceramics were decreased. The density of $(Bi_{0.1}Ba_{0.5}Sr_{0.4})TiO_3$ ceramics sintered at $1250^{\circ}C$ was 5.4524 [$g/cm^2$].

• Journal of the Korean Ceramic Society
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• v.43 no.7 s.290
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• pp.421-426
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• 2006

[ $(BaSr)TiO_3$ ] thick films were prepared by tape casting method, using $BaTiO_3\;and\;SrTiO_3$ powder slurry in order to investigate dielectric properties i.e. dielectric constant, ${\varepsilon}_r$, Curie temperature, $T_c$. Grain growth within $(BaSr)TiO_3$ thick films was observed with increasing weight ratio of $BaTiO_3$. This observation can be explained by phenomena of substitution of $Sr^{2+}$ ion for $Bi^{2+}$ ion in the $BaTiO_3$ system. Also, the Curie temperature in $(BaSr)TiO_3$ thick films was shifted to lower temperature range with increasing $ SrTiO_3$. Furthermore, Curie temperature having maximum dielectric constant was in the range of $-40^{\circ}C\;to\;30^{\circ}C$, and hence sharper phase transformation occurred at Curie temperature. There occurred decrease in tunability and k-factor of $(Ba_{0.6}Sr_{0.4})TiO_3$ calculated from the dielectric constant, ${\varepsilon}_r$ above Curie temperature. In addition, above the $60^{\circ}C$, phase fixation was observed. This means that internal stress relief occurred with increasing $90^{\circ}$ domains.

• Proceedings of the Materials Research Society of Korea Conference
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• 2002.05a
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• pp.57-57
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• 2002