• Title, Summary, Keyword: PZT

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Dielectric Properties of PZT(20/80)PZT(80/20) Heterolayered Thin Films Prepared by Sol-Gel Technique (Sol-Gel법으로 제조한 PZT(20/80)/PZT(80/20) 이종층 박막의 유전특성)

  • 이성갑;이영희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.11
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    • pp.990-995
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    • 1998
  • 본 연구에서는 PZT(20/80)과 PZT(80/20) 금속 alkoxide용액을 Pt/Ti/$SiO_2$/Si 기판위에 상호 반복시킨 강유전성 PZT(20/80)/PZT(80/20) 이종층 박막을 제작하였다. 건조와 소결을 한번 행한 PZT 이종층 박막의 평균 두께는 약 80~90 nm이었다. 제작된 모든 PZT 박막은 rosette상이 없는 치밀하고 균질한 미세구조를 나타내었으며, 하부의 PZT층은 열처리시 상부 PZT층은 열처리시 상부 PZT 박막의 페로브스카이트 형성에 대해 nucleation site로 작용하였다. 유전상수, 피로특성 및 누설전류특성 등은 단일 조성의 PZT(20/80), PZT(80/20) 박막에 비해 우수한 특성을 나타내었다.

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Effect of Composition and Coating of Precursor Solution on a Micro Structural Properties of PZT Thick Films (PZT 후막의 미세 구조적 특성에 조성과 전구체 용액의 코팅이 미치는 영향)

  • Park, Sang-Man;Noh, Hyun-Ji;Lee, Sung-Gap
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.11
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    • pp.1014-1019
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    • 2006
  • The influence of the number of solution coatings on the densification of the PZT thick films was studied. PZT powder and PZT precursor solution was prepared by a sol-gel method and PZT thick films were fabricated by the screen-printing method on the alumina substrates. The powder and solution of composition were (A) PZT(80/20)/PZT(20/80), (B) PZT(70/30)/PZT(30/70) and (C) PZT(60/40)/PZT(40/60), (D) PZT(52/48)/PT. The coating and drying procedure was repeated 4 times. And then the PZT precursor solution was spin-coated on the PZT thick films. A concentration of a coating solution was 0.5 moth and the number of coating was repeated from 0 to 6. The porosity of the thick films was decreased with increasing the number of coatings and the PZT thick films with 6-times coated showed the dense microstructure and thickness of about $60{\mu}m$. A grain size was increased with increasing the coating number. All PZT thick films showed the typical XRD patterns of a typical perovskite polycrystalline structure. The relative dielectric constant of PZT thick films was improved 30-100% as the number of coatings.

Pyroelectric Peyformance Evaluation of Pure PZT and Alternately Deposited PZT/PT Thin Films (PZT 순수박막과 PZT/PT 교차박막의 적외선 감지 특성 비교)

  • Ko, Jong-Soo;Kwak, Byung-Man
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.6
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    • pp.1001-1007
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    • 2002
  • To improve the performance of the PZT thin flms, each PZT and PT layer was alternately deposited on a Pt/Ti/Si$_3$N$_4$/SiO$_2$/Si substrate by a modified sol-gel solid precursor technique. For comparison, PZT thin films were also prepared with an identical method under the same conditions. XRD measurement revealed that the diffraction pattern of the multilayer film was due to the superimposition of the PZT and PT patterns. At 1㎑, a dielectric constant of 389 and 558, a dielectric loss of 1.2% and 1.1% were obtained for the PZT/PT and PZT thin films, respectively. If we consider the PT dielectric constant to be 260, it is clear that the dielectric constant of alternately deposited PZT/PT thin films was well adjusted. The PZT/PT thin film showed a low dielectric constant and a similar dielectric loss compared with those of the PZT film. The figures of merit on detectivity for the PZT/PT and PZT thin films were 20.3$\times$10$\^$-6/㎩$\^$-$\sfrac{1}{2}$/, and 18.7$\times$10$\^$-6/㎩$\^$-$\sfrac{1}{2}$/, and the figures of merit on voltage response were 0.038㎡/C and 0.028 ㎡/C, respectively. The high figures of merit for the PZT/PT film were ascribed to its relatively low dielectric constant when compared to the PZT thin films.

Structural and Electrical Properties of PZT(10/90)/PZT(90/10) Heterolayered Thin Films (PZT(10/90)/PZT(90/10) 이종층 박막의 구조적, 전기적 특성)

  • Lee, Seong-Gap;Kim, Gyeong-Tae;Bae, Seon-Gi;Lee, Yeong-Hui
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.49 no.2
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    • pp.98-102
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    • 2000
  • Ferroelectric PZT heterolayered thin films were fabricated by spin coating method on the Pt/Ti/SiO2/Si substrate using PZT(10/90) and PZT(90/10) m7etal alkoxide solutions. All PZT heterolayered films showed a homogeneous grain structures without presence of rosette structure. It can be assumed that the lower PZT layers played a role of nucleation site for the formation of the upper PZT layer. Pb-deficient PZT phase was formed at PZT/Pt interface due to the diffusion of Pb element into a Pt bottom electrode. The relative dielectric constant and the dielectric loss of the PZT-6 film were 567 and 3.6%, respectively. Increasing the number of coatings, remanent polarization and coercive field were decreased and the values of the PZT-6 heterolayered film were $7.18\muC/cm^2$ and 68.5kV/cm, respectively. Leakage current densities were increased with increasing the number of coatings, and the value of the PZT-4 film was about $7\times10-8A/cm^2$ at 0.05MV/cm.

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Structural and Dielectric Properties of PZT(20/80)/PZT(80/20) Heterolayered Thin Films Prepared by Sol-Gel Method (Sol-Gel법으로 제작한 PZT(20/80)/PZT(80/20) 이종층 박막의 구조 및 유전 특성)

  • 심광택;이영희
    • Electrical & Electronic Materials
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    • v.10 no.10
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    • pp.983-988
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    • 1997
  • We investigated the structural and dielectric properties of PZT(20/80)/PZT(80/20) heterolayered thin films that fabricated by the alkoxide-based Sol-Gel method. PZT(20/80)/PZT(80/20) heterolayered thin films were spin-coated on the Pt/Ti/SiO$_2$/Si substrate with PZT(20/80) film of tetragonal structure and PZT(80/20) film of rhombohedral structure by turns. Each layers were dried to remove the organic materials at 30$0^{\circ}C$ for 30min and sintered at $650^{\circ}C$ for 1hr. This procedure was repeated several times to form PZT(20/80)/PZT(80/20) heterolayered films and thickness of the film obtained by one-times of drying/sintering process was approximately 80-90nm. PZt-1, 3, 5 films with top layer of PZT(20/80) film of tetragonal structure showed fine grain structure and PZT-2, 4, 6 films with top layer of PZT(80/20) film of rhombohedral structure showed the dense grain microstructure without rosette-type. Dielectric constant and dielectric loss of the PZT-6 film were approximaterly 1385 and 3.3% respectively. Increasing the number of coatings remanent polarization was increased and coercive field was decreased and the values of the PZT-6 film were 8.13$\mu$C/cm$^2$and 12.5kV/cm respectively.

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Structural and Dielectrical Properties of PZT(30/70)/PZT(70/30) Heterolayered Thin Film Prepared by Sol-Gel Method (Sol-Gel법으로 제작한 PZT(30/70)/PZT(70/30) 이종층 박막의 구조 및 유전특성)

  • Kim, Gyeong-Gyun;Jeong, Jang-Ho;Lee, Seong-Gap;Lee, Yeong-Hui
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.7
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    • pp.514-520
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    • 1999
  • Ferroelectric PZT(30/70)/PZT(70/30) heterolayered thin films were fabricated by spin-coating method on the $Pt/Ti/SiO_2Si$ substrate alternately using(30/70) and PZT(70/30) alkoxide solutions prepared by sol-coating method. The coating and heating procedure was repeated six times to form PZT heterolayered films, and thickness of the film obtained by one-times drying/sintering process was about 40-50 nm. All PZT heterolayered films, showed dense and homogeneous structure without the presence of rosette sturctrue. The relative dielectric constant, remanent polarization and leakage current density of PZT heterolayered films were superior to those of single composition PZT(30/70) and PZT(70/30) films, and those values for the PZT-6 film were 975, $21 \muC/cm^2\; and\; 8\times10^{-9}\; A/cm^2$, respectively. And the PZT-6 heterolayered film showed fairly good fatigue characteristics of remanent polarization and coercive field after application of $10^8$ switching cycles.

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Piezoelectric PZT/Polymer Composite with 3-3 Connectivity (3-3 결합으로 이루어진 PZT/고분자 압전복합체)

  • 윤기현;염상덕
    • Journal of the Korean Ceramic Society
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    • v.25 no.2
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    • pp.125-130
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    • 1988
  • The characteristics of the PZT/PMM and PZT/Butadiene composites with 3 dimensional network structure have been investigated as a function of the PZT volume fraction. The dielectric constants of the PZT composites increased linearly as the PZT volume fraction increased. However, they are not significantly affected by the polymer compliance. The piezoelectric d33 coefficients of the PZT/Butadiene are largest than the PZT/PMM because of the high elastic compliance which promotes stress transfer. The values of the mechanical quality factor adn frequency factor of the PZT/PMM composite are slightly larger, while the planar coupling factor is smaller, than the PZT/Butadiene composite. These results are due to strong interaction and mechanical coupling between PZT and PMM.

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Microstructural Properties of PZT Heterolayered Thin Films Prepared by Sol-Gel Method (솔-젤법으로 제작한 PZT 이종층 박막의 구조적 특성)

  • 이성갑;김경태;정장호;박인길;이영희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.311-314
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    • 1999
  • Ferroelectric PZT heterolayered thin films were fabricated by spin coating method on the Pt/Ti/SiO$_2$/Si substrate using PZT(10/90) and PZT(90/10) metal alkoxide solutions. All PZT heterolayered films showed a homogeneous grain structure without presence of the rosette structure. It can be assumed that the lower PZT layers a role of nucleation site or seeding layer for the formation of the upper PZT layer. Zr and Ti diffusion into the Pt electrode were mainly distributed at the surface of Pt electrode beneath the PZT/Pt interface. The PZT/Pt interfacial layer showed a microstructure characterized by a grain phase surrounded by a Pb-deficient pyrochlore matrix phase. The relative dielectric constant and the dielectric loss of the PZT-6 film were 567 and 3.6, respectively.

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Electronic properties of PZT(20/80) thick film and PZT(80/20) thin film multilayer with variation of sintering temperature (다층 PZT(20/80)후막과 PZT(80/20)박막의 소결온도에 따른 전기적 특성)

  • Noh, Hyun-Ji;Lee, Sung-Gap;Park, Sang-Man;Bae, Seon-Gi
    • Proceedings of the KIEE Conference
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    • pp.2209-2210
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    • 2006
  • In this paper, PZT(20/80) thick films were fabricated by the screen-printing method. And the PZT(80/20) coating solution was synthesized by the sol-gel method. PZT(20/80) thick films were screen-printed on the alumina substrates. PZT(80/20) thin film was spin-coaled on the PZT(20/80) thick films to obtain densification. And the structural and electrical properties of PZT thick films were investigated with variation of sintering temperature. The PZT specimen sintered at $650^{\circ}C$ showed good relative dielectric constant of 219 and dielectric loss of 2.45%. Also the remanent polarization and the coercive field wore 16.48 ${\mu}C/cm^2$ and 35.48kV/cm, respectively.

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Structural properties of PZT multilayer thick films of improved densification (PZT 후막의 치밀성 향상에 따른 PZT 다층 후막의 구조적 특성)

  • Yun, Sang-Eun;Lee, Sung-Gap;Park, Sang-Man;Lee, Young-Hie
    • Proceedings of the KIEE Conference
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    • pp.2211-2212
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    • 2006
  • Ferroelectric PZT (70/30) thick films were fabricated by the screen printing method. And the PZT (30/70) precusor solution were infiltrated by the spin-coating method on the PZT thick films to obtain a densification. All PZT thick films were sintered at $1050^{\circ}C$ for 10 min. Structural properties, such as crystalline structure, microstructures and compositional ratio, of PZT thick films were investigated with the variation of the number of sol coatings using XRD, SEM and EDS, respectively. All PZT thick films exhibited a perovskite polycrystalline structure without a pyrochloer phase. The thickness of PZT thick films, 4-times screen-printed, was approximately $60{\mu}m$. And the densification of the PZT thick films increased with increasing the number of sol coatings.

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