Crystallographic orientation dependence of the dielectric constant in polymorphic BaNb2O6 thin films deposited by laser ablation

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

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Preparation and Characterization of Laser Ablation Derived PZT Thin Films for Micro Actuators

IEEJ Transactions on Sensors and Micromachines ◽

10.1541/ieejsmas.121.124 ◽

2001 ◽

Vol 121 (3) ◽

pp. 124-128

Author(s):

Zhan-Jie Wang ◽

Wen-Mei Lin ◽

Ryutaro Maeda

Keyword(s):

Thin Films ◽

Laser Ablation ◽

Pzt Thin Films ◽

Micro Actuators

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Microstructural and Electrical Characterization of Barium Strontium Titanatebased Solid Solution Thin Films Deposited on Ceramic Substrates by Pulsed Laser Deposition

MRS Proceedings ◽

10.1557/proc-720-h2.4 ◽

2002 ◽

Vol 720 ◽

Author(s):

Costas G. Fountzoulas ◽

Daniel M. Potrepka ◽

Steven C. Tidrow

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Pulsed Laser Deposition ◽

Pulsed Laser ◽

Electrical Characterization ◽

Field Variable ◽

Laser Deposition ◽

X Ray Diffraction ◽

Ceramic Substrates ◽

Nominal Thickness

AbstractFerroelectrics are multicomponent materials with a wealth of interesting and useful properties, such as piezoelectricity. The dielectric constant of the BSTO ferroelectrics can be changed by applying an electric field. Variable dielectric constant results in a change in phase velocity in the device allowing it to be tuned in real time for a particular application. The microstructure of the film influences the electronic properties which in turn influences the performance of the film. Ba0.6Sr0.4Ti1-y(A 3+, B5+)yO3 thin films, of nominal thickness of 0.65 μm, were synthesized initially at substrate temperatures of 400°C, and subsequently annealed to 750°C, on LaAlO3 (100) substrates, previously coated with LaSrCoO conductive buffer layer, using the pulsed laser deposition technique. The microstructural and physical characteristics of the postannealed thin films have been studied using x-ray diffraction, scanning electron microscopy, and nano indentation and are reported. Results of capacitance measurements are used to obtain dielectric constant and tunability in the paraelectric (T>Tc) regime.

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