The effect of Mg doping on the dielectric and tunable properties of Pb0.3Sr0.7TiO3 thin films prepared by sol–gel method

Abstract

Mg doped Pb 0.3 Sr 0.7 TiO 3 (PST) thin films were fabricated by the sol-gel method on a Pt/Ti/SiO 2 /Si substrate. The microstructure, surface morphology, dielectric and tunable properties of PST thin films were investigated as a function of Mg concentration. It is found that proper Mg doping dramatically improves the dielectric loss (0.0088 @ 1 MHz), furthermore, the crystallinity, dielectric constant, and tunability of films simultaneously decrease with the increase of Mg content. The 2 mol% Mg doped PST thin film shows the highest figure of merit (FOM) value of 36.8 for its the smallest dielectric loss and upper tunability. The dependence of Rayleigh coefficient on the doping concentration was examined, which indicated that the reduction of dielectric constant and tunability of films should be related to the Mg Ti -V •• O defect dipoles pinning the domain wall motion of residual polar clusters in PST.

Polymer‐based route to ferroelectric lead strontium titanate thin films

“…The shown hysteresis curve was measured after a pre‐loop with the same settings. Obtained polarization values (remanent polarization P r = 0.02 μC/cm 2 ) are smaller than previous reported measurements on thicker films . PST films produced by chemical solution deposition methods with thicknesses around 400 nm showed remanent polarizations ( P r ) between 1–2 μC/cm 2 .…”

“…Obtained polarization values (remanent polarization P r = 0.02 μC/cm 2 ) are smaller than previous reported measurements on thicker films . PST films produced by chemical solution deposition methods with thicknesses around 400 nm showed remanent polarizations ( P r ) between 1–2 μC/cm 2 . Films produced by physical vapor deposition methods like RF magnetron sputtering showed a remanent polarization of P r = 6 μC/cm 2 The polarization values of the PST films manufactured by direct UV‐lithography might be improved by using a multilayer approach to obtain thicker films and by improving the electrical contact between the film and the top electrode.…”

“…Because of their high values of ferroelectric polarization, piezoelectric coefficient, and dielectric permittivity ferroelectric films with perovskite structure like lead zirconate titanate (PbZr x Ti 1‐x O 3 , PZT), lead strontium titanate (Pb x Sr 1‐x TiO 3 , PST), and barium strontium titanate (Ba x Sr 1‐x TiO 3 , BST) films are widely used in the fields of sensors, energy harvesting, capacitors, and FeRAMs technology . PST and BST films can be used for tunable microwave device components, such as phase shifters, filters, varactors, and delay lines . PST thin films are promising candidates for these specific applications as PST thin films show lower loss tangent, larger tunability, and lower processing temperatures than BST thin films.…”

“…The films are deposited by different types of evaporation and sputtering techniques, for example, Pulsed Laser Deposition or RF Magnetron Sputtering . Chemical solution deposition methods especially by sol‐gel techniques have also been well investigated . Sol‐gel process offers the opportunity to produce very homogenous ceramic films.…”

Influence of annealing temperature on the microstructure, leakage current and dielectric properties of Na0.5Bi0.5(Ti,Zn)O3 thin films

“…In consideration of the nonlinear dependence of the relative dielectric constant (e r ) upon the applied electric field (E), it is also promising for using in tunable devices such as phase shifters, tunable oscillators and tunable filters [5,6]. Moreover, it is desirable to have high e r , low dissipation factor (tan d) and low leakage current density (J) for the ferroelectric materials used in tunable devices [7,8]. Leadbased materials have been widely used in the commercial market of the electronic industry, especially Pb(Ti,Zr)O 3 (PZT) due to the exceptional ferroelectric and dielectric properties [9].…”