Dielectric properties of sol–gel-derived MgO:Ba0.5Sr0.5TiO3 thin-film composites

Abstract

Alternate layer deposition of heterostructured magnesium oxide (MgO):barium strontium titanate (BST) thin films is demonstrated to be an approach to synthesize dielectric films with a higher figure of merit for microwave dielectric applications. The dielectric constant and the dielectric tunability are modified by MgO insertion. The dramatic reduction in the dielectric loss tangent effectively increased the figure of merit of the heterostructured thin films as compared to the pure BST films. The significant reduction in the dielectric loss tangent values has been attributed to the minute solid solubility of MgO in the BST lattice and the induced microstructural modifications induced by the MgO layers in thin films.

The fabrication and material properties of compositionally multilayered Ba1−xSrxTiO3 thin films for realization of temperature insensitive tunable phase shifter devices

“…Specifically, Table I summarizes literature derived dielectric properties, evaluated at 20°C, for single uniform composition BST films fabricated via sputtering, 40 PLD, 41 and sol-gel techniques. 42 In addition, reported literature results for proposed temperature stable material designs, namely, compositionally graded BST ͑Ref. 13͒ BST/MgO layered film structures, 42 are also listed in Table I along with our experimental results for the multilayered and single uniform composition BST thin films.…”

Study of leakage current in metal–insulator–metal Mg–Al co-doped barium strontium titanate thin films as a function of temperature and applied field

“…Various methods have been employed for fabricating BST thin films, such as radio frequency magnetron sputtering, pulsed laser deposition [5], liquid source misted chemical deposition [6], metal organic chemical vapor deposition [7], metal organic decomposition [8] and the sol-gel process [9]. The sol-gel method has been widely employed in the processing of thin films because of its many advantages, such as, easier composition control, better homogeneity, low processing temperature, fabrication of large area thin films, and low equipment cost.…”

Influence of anatase-rutile phase transformation on dielectric properties of sol-gel derived TiO2 thin films

“…Recently, TiO 2 thin films have been receiving new interest for their usage in high-k (dielectric constant) dielectrics in DRAMs with extremely small feature sizes (<100 nm) [5,6]. The dielectric properties of TiO 2 thin films, especially their dielectric constants, can be designed via many means such as through the formation of solid solutions [7] and mixtures [8] including the compositions of other oxides, the doping of ions [9], and the introduction of strain to thin films [10]. The dielectric properties of TiO 2 thin films can be also designed by controlling the phase transformation between the polymorphs (anatase, brookite and rutile phases) since these polymorphs possess different dielectric properties from each other [11].…”