Fabrication and Electrical Properties of Strain-Modulated Epitaxial Ba[sub 0.5]Sr[sub 0.5]TiO[sub 3] Thin-Film Capacitors

Abstract

Ba 0.5 Sr 0.5 TiO 3 ͑BST͒ epi layers 500 Å thick with different magnitudes of lattice distortion were fabricated by growing films on various perovskite oxide electrodes. The variations in the misfits between the BST and the bottom electrodes enable the strain manipulation of these BST epi layers. The 500 Å thick BST epi layer on the SrRuO 3 -coated SrTiO 3 ͑STO͒ substrate is almost completely constrained by the SrRuO 3 bottom electrode. The 500 Å thick BST epi layers are partially constrained on the Nb-doped STO, LaNiO 3 -coated STO, and La 0.7 Sr 0.3 MnO 3 -coated STO substrates. A suitable degree of lattice distortion of the BST epi layers is required to obtain a large dielectric constant; this fact is consistent with expectations based on the softening of the soft mode phonon. Variations to the electrical characteristics of the BST epi layers were considered with reference to changes in the degree of the lattice distortion of the BST epi layers.

Effects of growth temperature on structure and electrical properties of dielectric (Ba,Sr)TiO3 capacitors with transparent conducting oxide electrodes

“…As a result, BST thin films have been used in tunable microwave devices, electro-optic switches, capacitor applications in dynamic random access memory, and decoupling capacitors integrated into monolithic circuits [1][2][3]. These applications rely strongly on the excellent structural and electrical performance of BST films.…”

Effect of conductive oxide buffering on structural and nanoscale electrical properties of ultrathin SrTiO3 films on Pt electrodes

“…Composite electrodes were recently demonstrated to be effective in enhancing the electrical or crystalline properties of dielectric oxides from the crystallographic or chemical compatible points [4,5]. However, the effect of buffering of conductive oxide on the structural and electrical properties of the ultrathin STO films is lacking.…”

“…The RuO 2 and LNO are conductive oxides and have been used as electrodes for growth of perovskite oxides [5][6][7]. The effect of a conductive oxide buffer on the structural and electrical characteristics, and especially the nanoscale leakage current properties of ultrathin STO films, was studied herein.…”

Physical Properties of Strained Ba[sub 0.5]Sr[sub 0.5](Ti,Mn)O[sub 3] Thin Films Buffered with La[sub 0.68]Ba[sub 0.32]MnO[sub 3] Conductive Layers

“…Recently, conductive perovskite oxides have become attractive as electrode materials in BST capacitors because they have a similar crystalline structure and chemistry. [11][12][13] The perovskite electrodes provide a compatible interface for the dielectric oxide film, improving the quality and enhancing the dielectric properties of the deposited perovskite oxide films. Suitable interlayer ͑or buffer layer͒ materials with the same crystal structure as, but different lattice constants from, those of the capacitor material effectively improve the dielectric properties of thin capacitor materials.…”

“…Suitable interlayer ͑or buffer layer͒ materials with the same crystal structure as, but different lattice constants from, those of the capacitor material effectively improve the dielectric properties of thin capacitor materials. [12][13][14] In this study, LaNiO 3 ͑LNO͒ buffer layers on the Pt were employed to grow highly ͑001͒-textured La 0.68 Ba 0.32 MnO 3 ͑LBMO͒ bottom electrodes. LBMO with the perovskite structure is known to be a conducting ferromagnet.…”