Estudo da deposição de filmes finos de BaTi(1-X)Zr(X)O3 por meio de planejamento Box-Behnken
Ferroelectric ceramics with perovskite structure (ABO3) are widely used in solid state memories (FeRAM’s and DRAM's) as well as multilayered capacitors, especially as a thin films. When doped with zirconium ions, BaTiO3-based materials form a solid solution known as barium zirconate titanate...
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Formato: | Dissertação |
Idioma: | por |
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Universidade Federal do Rio Grande do Norte
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Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/20591 |
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Resumo: | Ferroelectric ceramics with perovskite structure (ABO3) are widely used in solid state
memories (FeRAM’s and DRAM's) as well as multilayered capacitors, especially as a thin
films. When doped with zirconium ions, BaTiO3-based materials form a solid solution known
as barium zirconate titanate (BaTi1-xZrxO3). Also called BZT, this material can undergo
significant changes in their electrical properties for a small variation of zirconium content in
the crystal lattice. The present work is the study of the effects of deposition parameters of
BaTi0,75Zr0,25O3 thin films by spin-coating method on their morphology and physical
properties, through an experimental design of the Box-Behnken type. The resin used in the
process has been synthesized by the polymeric precursor method (Pechini) and subsequently
split into three portions each of which has its viscosity adjusted to 10, 20 and 30 mPa∙s by
means of a rotary viscometer. The resins were then deposited on Pt/Ti/SiO2/Si substrates by
spin-coating method on 15 different combinations of viscosity, spin speed (3000, 5500 and
8000 rpm) and the number of deposited layers (5, 8 and 11 layers) and then calcined at 800 °
C for 1 h. The phase composition of the films was analyzed by X-ray diffraction (XRD) and
indexed with the JCPDS 36-0019. Surface morphology and grain size were observed by
atomic force microscopy (AFM) indicating uniform films and average grain size around 40
nm. Images of the cross section of the films were obtained by scanning electron microscopy
field emission (SEM-FEG), indicating very uniform thicknesses ranging from 140-700 nm
between samples. Capacitance measurements were performed at room temperature using an
impedance analyzer. The films presented dielectric constant values of 55-305 at 100kHz and
low dielectric loss. The design indicated no significant interaction effects between the
deposition parameters on the thickness of the films. The response surface methodology
enabled better observes the simultaneous effect of variables. |
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