• 한국세라믹학회지
• /
• 제32권12호
• /
• pp.1408-1416
• /
• 1995

Microstructure and ferroelectric properties of sol-gel derived PZT(52/48) and PT interlayered PZT(52/48) thin films on Pt/Ti/SiO2/Si substrates were investigated. Films were fabricated using Acetylacetone chelated PT and PZT(52/48) sols. PZT(52/48) thin films annealed at $700^{\circ}C$ for 20 min showed the rosette structure with the size of 1.2~1.6${\mu}{\textrm}{m}$ and the pyrochlore phse was contained. PT interlayered PZT thin films, which is inserted by PbTiO3 thin layer with the thickness of 130 $\AA$ between PZT thin film and electrode, consisted of a single perovskite phase after annealing above 55$0^{\circ}C$. They exhibited the uniform and columnar grains of 0.1~0.16${\mu}{\textrm}{m}$, which are applicable for microelectronic device including non-volatile memory. Typical P-E hysteresis loops could be obtained from PT interlayered PZT thin film at as low as the annealing temperature of 50$0^{\circ}C$. Ferroelectric properties of PT interlayered PZT thin films were improved as increasing annealing temperature up to $700^{\circ}C$, and then deteriorated at 75$0^{\circ}C$. PZT(52/48) and PT interlayered PZT(52/48) thin film annealed at $700^{\circ}C$ for 20 min displayed Ps=38.8$\mu$C/$\textrm{cm}^2$, Pr=10.0$\mu$C/$\textrm{cm}^2$, Ec=65.3 kV/cm and Ps=28.5$\mu$C/$\textrm{cm}^2$, Pr=9.8$\mu$C/$\textrm{cm}^2$, Ec=76.1 kV/cm, respectively.

• 전자공학회논문지D
• /
• 제35D권3호
• /
• pp.39-45
• /
• 1998

SrBi$_{2}$Ta$_{2}$O$_{9}$ (SBT) ferroelectric thin films for nonvolatile memory were prepared on Pt/Ti/SiO$_{2}$/Si and RuO$_{2}$/SiO$_{2}$/Si substrates by RF magnetron sputtering. The dependences of crystalline and electrical properties on the lower electrode type(Pt and RuO$_{2}$) and the annealing temperatures were investigated. SBT films regardless of their electrode types showed typeical Bi layered peroviskite crystal structures. The crystalline quality of as-deposited SBT films was improved by the rapid thermal annealing at 650.deg. C for 30 sec. The remanetn polarization of 2Pr (Pr+-Pr-) of the annealed SBT films deposited on Pt/Ti/SiO$_{2}$/Si substrates were about 11 .mu.C/cm$^{2}$ and 3 .mu.C/cm$^{2}$, respectively. The leakage currents at 3 V bias voltage were about 0.8 .mu.A/cm$^{2}$ for SBT/ Pt/Ti/SiO$_{2}$/Si and about 1 .mu.A/cm$^{2}$ for SBT/RuO$_{2}$/SiO$_{2}$/Si sample. SBT films annealed at 650 .deg. C showed no degradation in Pr values after 10$^{11}$ polarization switching cycles, indicating good fatigue properties. In addition, for SBT samples deposited on Pt/Ti/SiO$_{2}$/Si, Pr values increased to more than that of initial state, suggesting the increament of leakage current caused by repeated polarization.

• 한국재료학회지
• /
• 제6권6호
• /
• pp.610-617
• /
• 1996

강유전체 재료의 하부전극으로 사용되고 있는 Pt/Ti 박막의 접착력에 대한 열처리 분위기의 영향을 연구하였다. 시편의 접착력은 90$^{\circ}$ 필 테스트 방법을 사용하여 정량적으로 측정하였다. 열처리 후 사용된 분이기에 관계없이 모두 접착력이 감소하였는데 특히 산소분위기에서 열처리 한 시편의 접착력이 매우 크게 감소하였다. AES depth profile과 단면 TEM을 이용하여 계면반응을 관찰한 결과 산소열처리시에는 Ti가 외부에서 확산해 온 산소와 반응하여 rutile TiO2상이 형성됨을 알 수 있었다. 그러므로 산소열처리 후에 일어나는 접착력의 급격한 감소 원인은 열처리시 취약한 TiO2상이 형성되며 이로 인해 Ti 접착층이 고갈되기 때문임을 알 수 있었다.

• 한국세라믹학회지
• /
• 제28권2호
• /
• pp.101-108
• /
• 1991

0.2 mo1% La doped BaTiO3 samples were prepared by a wet chemical process (Pechini process) and electrical conductivity were measured from annealing temperatures(800-110$0^{\circ}C$) to room temperature continuously. 2 probe I-V characteristics showed that Pt electrodes were non-ohmic below about 80$0^{\circ}C$ for Ladoped sample. I-V curves showed varistor behavior and breakdown voltages showed PTC-like behavior. AC complex impedance of 0.2 La and 0.05 Mn mo1% doped BaTiO3 samples with three different electrodes (electroless Ni, Pt, Ag electrodes) were measured with temperature variation. Complex impedance plots showed that the samples with electroless Ni electrodes have negligible electrode resistance. Samples with Ag or Pt paste electrodes showed large electrode resistance. PTC effect, which is defined as the ratio of maximum resistance to minimum resistance, was found to be less than 10 for 0.2 mo1% La doped dense sample however greater than 105 with codoping of 0.05 mo1% Mn and 0.2 mol% La.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 C
• /
• pp.1488-1490
• /
• 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.

• 한국세라믹학회:학술대회논문집
• /
• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
• /
• pp.104.1-104
• /
• 2003

• 한국반도체및디스플레이장비학회:학술대회논문집
• /
• 한국반도체및디스플레이장비학회 2005년도 추계 학술대회
• /
• pp.68-72
• /
• 2005

본 논문에서는 $Bi_{3}Ti_{4}O_{12}$에 Nd를 치환했을 때 향상되는 강유전체 특성을 sol-gel 방법을 이용하여 분석하였다. 이를 위해 $10\;wt\%$의 $12\%$과량의 Bi가 첨가된 $Bi_{3.15}Nd_{0.85}Ti_{13}O_{12}$ sol-gel 용액을 제작하였다. BNT 박막은 $Pt/TiO_2/SiO_2/Si$ 기판 위에 스핀 코팅 방법을 이용하여 증착하였으며, 최종 증착된 박막의 조성은 Rutherford backscattering spectroscopy 분석을 이용하여 $Bi_{3.15}Nd_{0.85}Ti_{13}O_{12}$임을 확인하였다. 200 nm 두께의 BNT 박막은 XRD 분석을 통해 (117)방향에서 강한 피크가 나오며, (001) 방향에서 Nd 치환에 따른 효과로 억제된 피크가 나오는 것을 확인하였다. Pt/BNT/Pt 구조를 이용하여 잔류분극을 측정한 결과 7 V에서 $48\;{\mu}\;C/cm^2$ 이 나왔다. 이것은 다른 강유전체 물질인 PZT, SBT, BLT보다 월등히 큰 값이다.

• 청정기술
• /
• 제29권4호
• /
• pp.313-320
• /
• 2023

대표적인 비암모니아성 선택적 촉매환원반응기인 H₂-SCR의 활용성을 높이기 위하여 Ce를 조촉매로 활용한 PtNi/CeO₂-W-TiO₂의 촉매 분말을 합성하고 다공성 금속 구조(porous metal structure, PMS)에 코팅하여 선택적 촉매 환원에 의한 NOx 제거 특성을 평가하였다. CeO₂를 조촉매로 사용한 H₂-SCR은 CeO₂를 사용하지 않은 경우에 비해 더 높은 NOx 제거 효율을 나타내었으며, CeO₂ 담지율 10 wt%에서는 반응온도 90℃에서 가장 높은 제거효율을 보였다. 한편, 촉매구조체인 PMS의 촉매 코팅량이 증가함에 따라 NOx 제거효율은 90℃ 이하에서는 향상되었으나, 120℃ 이상에서는 감소하는 경향을 보였고 공간속도를 4,000 h^-1에서 20,000 h^-1로 변경한 경우, 120℃이상의 온도에서 NOx 제거 효율이 향상되는 것을 확인할 수 있었다.

• 한국전기전자재료학회논문지
• /
• 제34권6호
• /
• pp.466-474
• /
• 2021

[011] poled ternary Pb(In_1/2Nb_1/2)O₃-Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PIN-PMN-PT) single crystals have been investigated for active materials for acoustic transducers because of their high piezoelectric properties in both shear and transverse modes. In order to use [011] poled PIN-PMN-PT single crystals for acoustic transducers, the characterization of full-matrix material properties is required. In this study, full sets of compliance, dielectric, and piezoelectric constants of [011] poled rhombohedral PIN-PMN-PT were measured by a resonance method. Dimensions and geometries of 12 samples were proposed for measuring 17 independent material constants of [011] poled rhombohedral PIN-PMN-PT single crystals. Two sets of samples with different PT concentrations, 0.24PIN-0.49PMN-0.27PT and 0.24PIN-0.46PMN-0.30PT, were fabricated and their material properties were measured. Measured impedance spectra and simulated impedance spectra of the samples were compared to check the accuracy of the measurements.

• E2M - 전기 전자와 첨단 소재
• /
• 제9권10호
• /
• pp.991-1000
• /
• 1996

PbTiO$_{3}$-PbZrO$_{3}$-Pb(Ni$_{1}$3/Nb$_{2}$3/O$_{3}$) (PZT-PNN) thin films were prepared from corresponding metal organics partially stabilized with diethanolamine by the sol-gel spin coating method. Each mol ratio of PT:PZ:PNN solutions were #1(50:40:10), #2(50:30:20), #3(45:35:20), #4(40:40:20), #5(40:50:10), #6(35:45:20) and #7(30:50:20) respectively. The spin-coated PZT-PNN films were heat-treated at 350.deg. C for decomposition of residual organics, and were sintered from 450.deg. C to 750.deg. C for crystallization. The substrates, such as Pt and Pt/TiN/Ti/TiN/Si were used for the spin coating of PZT PNN films. The perovskite phase was observed in the PZT-PNN films heat-treated at 500.deg. C. The crystalline of the PZT-PNN films was optimized at the sintering of 700.deg. C. By the result of AES analysis, It is confirmed that the films of TiN/Ti/TiN was a good diffusion barrier and that co-diffusion into the each films was not observed.