Effect of Y doping and composition-dependent elastic strain on the electrical properties of (Ba,Sr)TiO3 thin films deposited at 520 °C

Abstract

We demonstrate that large and simultaneous improvements in permittivity, tunability, and leakage current density of (Ba,Sr)TiO3 (BST)-based thin-film capacitors can be achieved by yttrium doping. We have found that, for a low deposition temperature (520 °C) sputtering process, Y-doped BST capacitors exhibit tenfold lower leakage current density (<10−9A∕cm2 at 100KV∕cm) and 70% higher permittivity than nominally undoped BST-based capacitors. Furthermore, this work suggests an intriguing correlation between dopant concentration-dependent elastic strain in the films and their enhanced dielectric properties.

The Influence of Film Thickness on the Transparency and Conductivity of Al-Doped ZnO Thin Films Fabricated by Ion-Beam Sputtering

“…2. The undoped ZnO thin films were prepared using the ion-beam sputtering method, and the corresponding unstressed lattice parameter d 0 (2.6286 Å ) is found to be higher than that (2.6035 Å ) 20 of bulk ZnO materials of similar composition, which is similar to the result of Wang et al 21 The residual stress calculation is based on the biaxial strain model, and the following formula is used: 22…”

The structure and dielectric properties of a novel kind of doped Ba0.6Sr0.4TiO3 film

“…[21] owing mainly to different substrates and film preparation methods. For similar reasons, the permittivity of our Mn-BST film is different from that of the Mn-BST film deposited on La 0.67 Sr 0.33 MnO 3 coated single-crystal (001) oriented LaAlO 3 substrates using pulsed-laser deposition technique [28].…”

Unusual thickness dependence of permittivity and elastic strain in Sc modified epitaxial (Ba,Sr)TiO3 thin films

“…[4][5][6] Doping may also modify the lattice strain but there have been conflicting experimental reports on the relationship between the lattice distortion or elastic strain induced by doping and the dielectric properties in doped ATiO 3 thin films. [8][9][10] Studies of nonepitaxial ͑Ba, Sr͒Ti 1−x Y x O 3 and ͑Ba 0.25 ,Pb 0.25 ͒Sr 0.5 TiO 3 thin films found lattice parameters altered by incorporation of dopant as well as enhanced permittivity and tunabilty. 8,10 In contrast, no difference in the lattice parameters of undoped and Er doped films was found and a decrease in permittivity and tunability with dopant reported.…”

“…[8][9][10] Studies of nonepitaxial ͑Ba, Sr͒Ti 1−x Y x O 3 and ͑Ba 0.25 ,Pb 0.25 ͒Sr 0.5 TiO 3 thin films found lattice parameters altered by incorporation of dopant as well as enhanced permittivity and tunabilty. 8,10 In contrast, no difference in the lattice parameters of undoped and Er doped films was found and a decrease in permittivity and tunability with dopant reported. 9 In this letter, we demonstrate that the elastic strain and k can be modified in epitaxial BST thin films by adding Sc dopant and that doping can be used as a potential design factor in epitaxial BST thin films to adjust the thickness dependence of k.…”