• Title/Summary/Keyword: Ferroelectric thin films

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Fabrication and Characterization of the BLT/STA/Si Structure for Fe-FETs Application

  • Park, Kwang-Huna;Jeon, Ho-Seung;Park, Jun-Seo;Im, Jong-Hyun;Park, Byung-Eun;Kim, Chul-Ju
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.73-74
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    • 2006
  • Ferroelectric thin films have been widely investigated for future nonvolatile memory application. We fabricated the BLT ($(Bi,La)_4Ti_3O_{12}$) films on Si using a STA ($SrTa_2O_6$) buffer layer BLT and STA film were prepared by sol-gel method. Measurement data by XRD and AFM, showed that BLT film and STA films were well crystallized and a good surface morphology. From C-V measurement reward that the Au/BLT/STA/Si structure showed a clockwise hysteresis loop with a memory window of 1.5 V for the bias voltage sweep of ${\pm}5$ V. From results, the Au/BLT/STA/Si structure is useful for FeFETs.

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Pyroelectric infrared microsensors made by micromachining technology (마이크로 가공 기술을 이용한 강유전체 박막 초전형 적외선 센서)

  • 최준임
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.4
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    • pp.93-100
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    • 1998
  • Pyoelectric infrared detectors based on La-modified PbTiO3 (PLT) thin films have been fabricated by RF magnetron sputtering and micromachining technology. The detectors form Pb$_{1-x}$ La$_{x}$Ti$_{1-x}$ O$_{3}$ (x=0.05) thin film ferroelectric capacitors epitaxially grown by RF magnetron sputtering on Pt/MgO (100) substrate. The sputtered PLT thin film exhibits highly c-axis oriented crystal struture that no poling trealization for sensing applications is required. This is an essential factor to increase the yield for realization of an infrared image sensor. Micromachining technology is used to lower the thermal mass of the detector by giving maximum sensor efficiency. Polyimide is coated on top of the sensing elements to support the fragile structure and the backside of the MgO substrate is selectively eteched to reduce the heat loss. The sensing element exhibited a very high detectivity D* of 8.5*10$^{8}$ cm..root.Hz/W at room temperature and it is about 100 times higher than the case of micromachining technology is not used. a sensing system that detects the position as well as the existence of a human body is realized using the array sensor.sor.

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Fabrication of PZT Film by a Single-Step Spin Coating Process

  • Oh, Seung-Min;Kang, Min-Gyu;Do, Young-Ho;Kang, Chong-Yun;Nahm, Sahn;Yoon, Seok-Jin
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.193-193
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    • 2011
  • To obtain ceramic films, the sol-gel coating technique has been broadly used with heat treatment, but crack formation tend to occur during heat treatment in thick sol-gel films. We prepared PZT thin films by sol-gel method with single-step spin coating process. The PZT solution have been synthesized using lead acetate ($Pb(CH_3COO)_2$), zirconium acetylacetonate ($Zr(OC_3H_7^n)_4$), and titanium diisopropoxide bis(acetylacetonate) 75wt% in isopropanol ($Ti(OC_3H_7^i)_2(OC_3H_7^n)_2$) as starting materials and n-propanol was selected as a solvent. The poly(vynilpyrrolidone) (PVP) was added with 0, 0.25, 0.5, 0.75, and 1 molar ratios to control viscosity of solution. We investigated influence of the viscosity on thickness, microstructure, and electrical properties of final PZT films. Thermo-gravimetric analysis and differential scanning calorimeter (TGA/DSC) was carried out from room temperature to $800^{\circ}C$ in order to measure pyrolysis temperature. Structural characteristics were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ferroelectric and dielectric properties were measured by RT66A (Radiant) and impedance analyzer (Agilent), respectively. The thicknesses of PZT films depended on incorporation of an excess amount of PVP. Finally, we obtained PZT films of good quality without crack formation via single-step spin coating.

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Fabrications and properties of MFIS structure using AIN buffer layer (AIN 버퍼층을 사용한 MFIS 구조의 제작 및 특성)

  • 정순원;김용성;이남열;김진규;정상현;김광호;유병곤;이원재;유인규
    • Proceedings of the IEEK Conference
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    • 2000.11b
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    • pp.29-32
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    • 2000
  • Meta1-ferroelectric-insulator-semiconductor(MFIS) devices using Pt/LiNbO$_{3}$/AIN/Si structure were successfully fabricated. AIN thin films were made into metal-insulator-semiconductor(MIS) devices by evaporating aluminum in a dot array on the film surface. The dielectric constant of the AIN film calculated from the capacitance in the accumulation region in the capacitance-voltage(C-V ) characteristic is 8. The gate leakage current density of MIS devices using a aluminum electrode showed the least value of 1$\times$10$^{-8A}$ $\textrm{cm}^2$ order at the electric field of 500㎸/cm. A typica] value of the dielectric constant of MFIS device was about 23 derived from 1MHz capacitance-voltage (C-V) measurement and the resistivity of the film at the field of 500㎸/cm was about 5.6$\times$ 10$^{13}$ $\Omega$.cmcm

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Ferroelectric properties of Pb[(Zr. Sn)Ti]NbO$_3$Thin Films prepared by RF Magnetron Sputtering Method (RF 마그네트론 스퍼터링 방법으로 제작된 Pb[(Zr. Sn)Ti]NbO$_3$박막의 강유전 특성)

  • 최우창;최혁환;이명교;권태하
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.199-202
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    • 1999
  • 반강유전 물질인 Pb[(Zr. Sn)Ti]NbO₃를 La/sub 0.5/Sr/sub 0.5/CoO₃/Pt/Ti/SiO₂/Si 기판상에 RF 마그네트론 스퍼터링 방법으로 박막화하여 그 결정성과 전기적 특성을 조사하였다. 80 W의 RF power, 400℃의 기판온도, Ar:O₂= 9:0.5의 분위기에서 증착되고, 650 ℃에서 10초동안 RTP(Rapid Thermal Process) 방법으로 열처리된 박막이 가장 우수한 페로브스카이트 구조를 보였으며, 10 ㎑ 에서 유전상수(ε')는 721, 유전손실(tan δ)은 0.06을 나타내었다. 잔류분극(Pr)은 15.5 μC/㎠ 였으며, 항전계(Ec)는 51 ㎸/㎝로 비교적 낮은 값을 나타내었다.

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The properties of $(Ba_{0.7}\;Sr_{0.3})TiO_3$ by Multilayer structure (다층 구조에 의한 $(Ba_{0.7}\;Sr_{0.3})TiO_3$의 물리적 특성)

  • Hong, Kyung-Jin;Cho, Jae-Cheal
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.05a
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    • pp.31-34
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    • 2006
  • In this study, $(Ba_{0.7}\;Sr_{0.3})TiO_3$ was coated on Pt/Ti/$SiO_2$/Si wafer by using Sol-Gel method. Coating process was repeated 3~5 times and then sintered at 750[$^{\circ}C$] for 1 hour. Each specimen was analyzed structure and electrical characteristics. In structure characteristics, EDX analyzed the samples ratio of the formation on the structural property. Thermal behavior was observed with TG-DTA and concluded that the heat-treatment of the samples was degreed 750[$^{\circ}C$]. Surface and section of thin films were observed with SEM.

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Ferroelectric and ferromagnetic properties of $BiFeO_3-PrFeO_3-PbTiO_3$ solid solutions ($BiFeO_3-PrFeO_3-PbTiO_3$계의 강자성-강유전 특성)

  • Kim, Jeong-Seog;Cheon, Chae-Il;Park, Yong-Nam;Jang, Pyung-Woo
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.40-41
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    • 2002
  • Synthesis of the ferroelectromagnetic material exhibiting ferromagnetism and ferroelectricity simultaneously has been an interesting subject due to not only for a possible application in electronic devices but also from the view point of solid state physics. In this study bulk ceramics and thin films of xBiFeO$_3$-yPrFeO$_3$-zPbTiO$_3$(x+y+z=1) and (1-w)BiFeO$_3$-wPbTiO$_3$ have been explored for finding ferroelectromagnetic material, in which ferroelectricity and ferromagnetism coexist simultaneously. (omitted)

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Preparation and Characteristics of Ferroelectric $\textrm{SrBi}_{2}\textrm{Ta}_{2}\textrm{O}_{9}$ Thin Films Deposited by Plasma-Enhanced Metalorganic Chemical Vapor Deposition Technique with Various Deposition Temperatures (PEMOCVD에 의한 강 유전체 $\textrm{SrBi}_{2}\textrm{Ta}_{2}\textrm{O}_{9}$박막의 제조 및 증착온도 특성)

  • Seong, Nak-Jin;Yun, Sun-Gil
    • Korean Journal of Materials Research
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    • v.7 no.5
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    • pp.381-385
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    • 1997
  • PEMOCVD에 의해서 SrBi$_{2}$Ta$_{2}$O$_{9}$밥막이 낮은 온도에서 성공적으로 Pt/Ti/SiO$_{2}$Si위에 증착되었다. 5$50^{\circ}C$에서 증착된 200nm박막은 치밀하고 작은 결정립을 보였으며 3V의 인가전압하에서 이력곡선은 포화되기 시작하였다. 3V에서 박막은 잔류분극 (P$_{r}$)과 항전계(E$_{c}$)는 각각 15$\mu$/$\textrm{cm}^2$과 50kV/cm이었다. 6V bipolar square pulse의 피로측정에서 박막은 1.0x$10^{11}$cycles까지 피로 현상을 보이지 않았다. PEMOCVD에 의해서 5$50^{\circ}C$에서 증착된 SBT박막은 비휘발성 기억소자에 충분히 활용할 수 있다.다.

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Ferroelectric Properties of Sol-Gel Derived pb(Zr,Ti)$\textrm{O}_3$Thin Films (SoI-Gel법에 의한 Pb(Zr, Ti)$\textrm{O}_3$박막의 강유전체 특성)

  • Go, Ga-Yeon;Lee, Eun-Gu;Park, Jin-Seong;Lee, Jong-Guk;Lee, U-Seon;Lee, Jae-Gap
    • Korean Journal of Materials Research
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    • v.7 no.6
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    • pp.479-483
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    • 1997
  • Sol-gel법으로 제작한 여러 종류의 Zr/Ti비율을 갖고 있는 PZT박막의 전지적 특성과 신뢰성 특성을 상부 백금 전극을 sputtering으로 증착하고 Ar 기체로 반응성 이온 식각(RIE)방법으로 패턴을 형성한 후 열처리온도의 변화에 따라 조사하였다. Hysteresis loop특성을 되찾게 하였다. Zr/Ti 비율이 감소함에 따라 voltage shift가 증가하였으며 internal field가 없어지는 열처리 온도가 증가하였다. Zr/Ti비율이 감소함에 따라 초기 잔류 분극은 증가하였으나 switching 횟수가 증가됨에 따라 잔류 분극이 급속히 감소하였다.

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