Processing and dielectric characterization of Ba0.3Sr0.7TiO3 thin films on alumina substrates

Electrical Characterizations of Lead Free Sr and Sn Doped BaTiO3 Ferroelectric Films Deposited by Sol-Gel

“…The mean grain size of this film is about 110 nm against 60 nm for the film annealed at 750 °C. This increase is in agreement with our XRD patterns and with other results on BST films (Malic et al, 2007). Moreover, the surface observation shows a rather good density of grains without cracks.…”

“…So, the annealing duration at 950 °C has no effect on the grain size with a maximum of one hour duration. This is in agreement with other works on BST thin films (Malic et al, 2007). From figure 12.a we can see clearly that the tunability is correlated with the grain size.…”

Combined effects of thickness, grain size and residual stress on the dielectric properties of Ba0.5Sr0.5TiO3 thin films

“…In the same thickness range the porosity is reduced. However, the trend of permittivity increase is similar to the one observed in Ba 0.3 Sr 0.7 TiO 3 thin films on alumina substrates, i.e., a grain-size increase from 40 to 80 nm results in a doubling of the dielectric permittivity, meaning that the grain size clearly controls the dependence of the dielectric permittivity [43]. The residual tensile stress in a 90-nm-thick film is As the thickness and grain size increase from 170 to 240 nm and from 75 to 90 nm, respectively, only a slight change in the permittivity is observed (Figure 1 and Figure 6), which indicates a deviation from the previously observed grain-size effect.…”

“…As examples, the reported out-of-plane permittivity of ∼300-nm-thick RF-sputtered BST films prepared at 600 °C on platinized silicon substrates (Ba/Sr = 50/50) with 82 nm large grains is 760 at 100 kHz [17], while the in-plane permittivity of PLD-deposited 200-nm-thick films (Ba/Sr = 60/40) on r-sapphire with grains in the 50-100 nm range is 830 at 10 GHz [21]. Besides the grain size and the thickness of the films, additional parameters that strongly influence the permittivity value are the grain morphology and porosity [26,27,43,44]. We ascribe the good dielectric properties of the films to optimized processing conditions, i.e., the separation of the drying/pyrolysis/annealing steps for the efficient removal of the organics and the high heating rate and annealing temperature of 900 °C, resulting in a dense and predominately columnar microstructure [27].…”

Dielectric Response of BaTiO3 Thin Film with Grain Size at Nanometer Scale

“…The presence of intergranular porosity is also seen. A similar type of microstructure has been previously reported for solution‐derived alkaline‐earth titanate thin films . The AFM analysis of the BTO surface topography was performed using scan areas from (5 μm × 5 μm) to (0.5 μm × 0.5 μm).…”