Low-temperature processing of sol-gel derived Pb(Zr,Ti)O3 thick films using CO2 laser annealing

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• 作者：Chen-Chia Chou ; Shen-Da Tsai ; Wen-Hsiang Tu ; Yu-En Yeh-Liu and Hsien-Lung Tsai
• 关键词：Laser annealing ; Sol ; gel ; Ferroelectric ; PbZrTiO3 ; Thick films
• 刊名：Journal of Sol-Gel Science and Technology
• 出版年：2007
• 出版时间：June, 2007
• 年：2007
• 卷：42
• 期：3
• 页码：315-322
• 全文大小：796 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Ceramics,Glass,Composites,Natural Materials
  Inorganic Chemistry
  Optical and Electronic Materials
  Nanotechnology
  
• 出版者：Springer Netherlands
• ISSN：1573-4846

文摘

Fabrication of ferroelectric Pb(Zr_0.52Ti_0.48)O₃ (PZT) thick films on a Pt/Ti/SiO₂/Si substrate using powder-mixing sol-gel spin coating and continuous wave CO₂ laser annealing technique to treat the specimens with at a relatively low temperature was investigated in the present work. PZT fine powders were prepared by drying and pyrolysis of sol-gel solutions and calcined at temperatures from 400 to 750°C. After fine powder-containing sol-gel solutions were spin-coated on a substrate and pyrolyzed, CO₂ laser annealing was carried out to heat treat the specimens. The results show that laser annealing provides an extremely efficient way to crystallize the materials, but an amorphous phase may also form in the case of overheating. Thicker films absorb laser energy more effectively and therefore melt at shorter periods, implying a significant volume effect. A film with thickness of 1 μm shows cracks and rough surface morphology and it was difficult to obtain acceptable electrical properties, indicating importance of controlling interfacial stress and choosing appropriate size of the mixing powders. On the other hand, a thick film of 5 μm annealed at 100 W/cm2 for 15 s exhibits excellent properties (P _r = 36.1 μC/cm2, E _c = 19.66 kV/cm). Films of 10 μm form a melting zone at the surface and a non-crystallized bottom layer easily at an energy density of 100 W/cm2, showing poor electrical properties. Besides, porosity and electrical properties of thick films can be controlled using appropriate processing parameters, suggesting that CO₂ laser annealing of modified sol-gel films is suitable for fabricating films of low dielectric constants and high crystallinity.