• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2002년도 추계학술대회 발표 논문집
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• pp.69-71
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• 2002

$(Bi, La)Ti_{3}O_{12}(BLT)$ ferroelectric thin films were prepared on $Al_{2}O_{3}/Si$ substrates by the sol-gel method. The as-coated films were post-annealed at the temperature of $650^{\circ}C$ and $700^{\circ}C$ for 30 min. The crystallinty, surface morphologies and electrical properties were affected by the annealing temperatures. The BLT films annealed at above $650^{\circ}C$ exhibited typical bismuth layered perovskite structures with (00$\ell$) preferred orientation. The granular shaped grains with a size of approximately 90nm was formed in the film sample annealed at $700^{\circ}C$. The memory window volatge of the BLT film was 2.5V. The leakage current of BLT films annealed at $650^{\circ}C$ was about $1\times10^{-7}A/\textrm{cm}^2$ at 3V.

• 대한수의학회지
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• 제31권1호
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• pp.71-75
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• 1991

소의 순환혈액 및 림프조직내의 T 및 B 림프구의 분포를 파악하고자 소흉선 세포를 토끼에 과면역시켜 얻은 항혈청을 소의 적혈구, 간장분말 및 골수세포에 순차적으로 흡착시킨 항 흉선 세포혈청(RABTS)과 성숙 T 림프구에만 특이성을 가진 단클론항체 $BLT_1$ 및 B 림프구와 소수의 대식세포에 특이성을 가진 단클론항체 $_6E_{12}$를 1차 항체로 이용하여 ABPC법으로 T 및 B 림프구를 동정한 바 다음과 같은 결과를 얻었다. RABTS 및 $BLT_1$으로 동정한 순환혈액내 단핵세포(PB-MNCs) 중 T림프구의 비율은 각각 70.9${\pm}5.5%$ 및 $59.0{\pm}8.7%$이었으며, PB-MNCs중 nylon wool 비부착세포를 $BLT_1$ 및 $_6E_{12}$로 동정한 T 및 B 림프구의 비율은 각각 $91.6{\pm}1.0%$, $9.6{\pm}0.8%$이었다. 또한 $BLT_1$ 및 $_6E_{12}$로 동정한 서혜림프절, 장간막 림프절, 비장 및 흉선의 T/B림프구의 비율은 각각 $56.4{\pm}6.2/45.3{\pm}7.4%$, $55.6{\pm}7.7/42.3{\pm}5.8%$, $48.6{\pm}5.1/48.5{\pm}6.2%$ 및 $23.0{\pm}4.8/5.6{\pm}2.1%$이었으며, RABTS로 동정한 이들 림프조직내의 T림프구의 비율은 각각 $76.3{\pm}3.4%$, $74.2{\pm}8.2%$, $73.6{\pm}5.5%$ 및 $95.6{\pm}2.8%$이었다. 이상의 결과로 미루어 PB-MNCs네의 T림프구 분리는 nylon wool column법이 보다 효과적임을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제20권7호
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• pp.575-580
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• 2007

A 16 Mb 1T1C FeRAM device was integrated with BLT capacitors. But a lot of cells were failed randomly during the measuring the bit-line signal distribution of each cell. The reason was revealed that the grain size and orientation of the BLT thin film were severely non-uniform. And the grain size and orientation were severely affected by the process conditions of post heat treatment, especially nucleation step. The optimized annealing temperature at the nucleation step was $560^{\circ}C$. The microstructure of the BLT thin film was also varied by the annealing time at the step. The longer process time showed the finer grain size. Therefore, the uniformity of the grain size and orientation could be improved by changing the process conditions of the nucleation step. The FeRAM device without random bit-fail cell was successfully fabricated with the optimized BLT capacitor and the sensing margin in bit-line signal distribution of it was about 340 mV.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2002년도 춘계학술발표논문집
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• pp.121-123
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• 2002

졸-겔법(Sol-Gel Method)으로 강유전체 Bi/sub 3.3/La/sub 0.7/Ti/sub 3/O/sub 12/(BLT) 박막을 Pt/Ti/SiO₂/Si 기판위에 스핀 코팅하여 Metal-Ferroelectric-Metal(MFM 구조를 형성하였다. As-coated BLT 박막은 650℃ 이상에서 결정화되었으며, 전형적인 Bi층상의 페롭스카이트 결정구조를 나타내었다. 또한 열처리 온도를 증가시킴에 따라 결정성이 향상되었다. 3V 전압에서 650℃로 열처리된 박막의 경우 누설전류가 약 2.25×10/sup -8/A/㎠ 정도를 보였다. 650℃에서 열처리된 BLT박막은 5V의 인가 전압에서 잔류분극 2Pr(±(P/sup */-P/sup A/)) 값은 약 29.5μC/㎠을 나타내었으며, 1.5×10/sup 10/ 스위칭 cycles까지 분극 스위칭을 반복한 후에도 거의 잔류 분극의 변화가 없었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.368-369
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• 2006

Ferroelectric thin films have attracted much attention for applications in nonvolatile ferroelectric random access memories(NVFeRAM) from the view points of high speed operation, low power consumption, and large scale Integration[1,2]. Among the FRAM, BLT is of particular interest. as it is not only crystallized at relatively low processing temperature, but also shows highly fatigue resistance and large remanent polarization Meanwhile, these submicron ferroelectric capacitors were fabricated by a damascene process using Chemical mechanical polishing (CMP). BLT capacitors were practicable by a damascene process using CMP. The P-E hysteresis were measured under an applied bias of ${\pm}5V$ by using an RT66A measurement system. The electric properties such as I-V were determined by using HP4155A analysers.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2002년도 추계기술심포지움논문집
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• pp.69-72
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• 2002

B $i_{3.3}$L $a_{0.7}$ $Ti_3$ $O_{12}$(BLT) 강유전체 박막을 $Al_2$ $O_3$/Si 기판위에 졸-겔(sol-gel)법으로 스핀 코팅하여 Metal-Ferroelectric-Insulator-Silicon (MFIS) 구조를 형성하였다. 박막의 결정화를 위해 as-coated 박막을 산소분위기에서 $650^{\circ}C$ 및 $700^{\circ}C$에서 30분 동안 후속열처리를 실시하였다. BLT 박막의 열처리 온도를 $650^{\circ}C$에서 $700^{\circ}C$로 증가시킴에 따라서 c축으로 우선 배향되는 경향을 보였으며, FWHM 값이 감소하여 결정성이 향상됨을 확인할 수 있었다. $700^{\circ}C$에서 열처리된 BLT 박막의 memory window는 약 2.5V (인가전압 5V)를 나타내었으며, 누설전류는 약 1.5x$10^{-7}$ A/$\textrm{cm}^2$를 나타내었다.다.다.

• 한국재료학회지
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• 제14권10호
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• pp.701-706
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• 2004

Bismuth layered structure ferroelectric thin films, La-substituted $Bi_{4}Ti_{3}O_{12}$ ($Bi_{1-x}La_{x}Ti_{3}O_{12}$, x=0.75, BLT) were prepared on the $Pt(111)/Ti/SiO_2/Si(100)$ substrates by a sol-gel spin coating process. The thin films were annealed in various conditions, i.e., oxygen, nitrogen and vacuum atmospheres for various annealing time. We investigated the annealing condition effects on the grain orientation and ferroelectric properties. The measured XRD patterns revealed that the BLT thin films showed only $Bi_{4}Ti_{3}O_{12}$-type phase with random orientation. $La^{3+}$ ion substitution for $Bi^{3+}$ ion in perovskite layers of $Bi_{4}Ti_{3}O_{12}$ decreased the degree of c-axis orientation and increased the remanent polarization ($2P_{r}$). The remanent polarization ($2P_{r}$) and the coercive field ($2E_{c}$) of the BLT thin film annealed at $650^{\circ}C$ for 5 min in oxygen atmosphere were $87{\mu}C/cm^2$ and 182 kV/cm, respectively, at an applied electric field of 240 kV/cm. For all of the BLT thin films annealed in various conditions, the fatigue resistance was shown. The improvement of ferroelectric properties with La substitution in $Bi_{4}Ti_{3}O_{12}$ could be attributed to the changes in space charge densities and grain orientation in the thin film.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.463-466
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• 2001

In recent year, Ferroelectric BLT($Bi_{4-x}$La$_{x}$Ti$_3$O$_{12}$) is a promising candidate materials. This study was Practiced to make good conditions of BLT targets. In this study, calcination and sintering temperature were kept at 75$0^{\circ}C$, 110$0^{\circ}C$ for 2 hour respectively. the density obtained 7.612, 7.98, 7.877 g/㎤ as La$_2$O$_3$ contents were 0.0mol%, 0.25mo1%, 0.5mol%. Especially, the lanthanum content of 0.5 mol% measured C-axis (117) preferred orientation more than the others targets in the XRD. In $\varepsilon$$_{r}$-f relationship using by HP 4194 A impedance analyzer, the 0.5 mol% observed above 200 relative dielectric constant. but the dissipation factor was higher than others targets at 100Hz~13MHz range. SEM photograph with the content of La$_2$O$_3$ was observed like rod and plate types.types.s.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.533-534
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• 2006

1mm-thick BLT ceramics were sintered in accordance with a bulk ceramic fabrication process. All XRD peaks detected in the sintered ceramics were indexed as the Bi-layered perovskite structure without secondary phases. Density was increased with increasing the sintering temperature up to $1050\;^{\circ}C$ and the maximum value was about 98% of the theoretical density. The remanent polarization (2Pr) value of BLT ceramic sintered at $1050\;^{\circ}C$ was approximately $6.5\;{\mu}C/cm^2$ at the applied voltage of 4.5kV. From these results, a BLT ceramic target for plused laser deposition (PLD) system was successfully fabricated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.276-277
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• 2006

1mm-thick BLT ceramics were sintered in accordance with a bulk ceramic fabrication process. AII XRD peaks detected in the sintered ceramics were indexed as the Bi-layered perovskite structure without secondary phases. Density was increased with increasing the sintering temperature up to $1050^{\circ}C$ and the maximum value was about 98% of the theoretical density. The remanent polarization (2Pr) value of BLT ceramic sintered at $1050^{\circ}C$ was approximately $6.5\;{\mu}C/cm^2$ at the applied voltage of 4.5 kV. The calculated electromechanical coupling factor ($k_t$) of it was about 5% and the mechanical quality factor (Qm) was about 2200. From these results, a BLT ceramic target for pulsed laser deposition (PLD) system was successfully fabricated.