Crystal Orientation Control of Bismuth Layer-Structured Dielectric Films Using Interface Layers of Perovskite-Type Oxides

Abstract

Thin films of SrBi4Ti4O15, a kind of bismuth layer-structured dielectrics (BLSDs), were prepared on platinized silicon wafers buffered by perovskite-type oxide interface layers, (100)LaNiO3/(111)Pt/TiO2/(100)Si and (001)Ca2Nb3O10-nanosheets/(111)Pt/TiO2/(100)Si, by chemical solution deposition (CSD). The Ca2Nb3O10 nanosheets were supported on a (111)Pt/TiO2/(100)Si substrate by dip coating using an aqueous dispersion, while (100)LaNiO3 was prepared by CSD. The (00l) planes of BLSD crystal were preferentially oriented on the surface of both substrates, which is caused by suitable lattice matching between the a-(b-)axis of BLSD and perovskite-type oxide layers. The film deposition on (001)Ca2Nb3O10 nanosheets yielded (001)-oriented BLSD films with higher crystallinity and smaller fluctuation in the tilting angle of the (001)BLSD plane than those on the (100)LaNiO3 interface layer. The dielectric constant (εr) of (001)-oriented SrBi4Ti4O15 film on (001)Ca2Nb3O10-nanosheets/(111)Pt/TiO2/(100)Si substrate was approximately 190, which was significantly stable against the change of frequency and bias voltage compared with that of the randomly-oriented SrBi4Ti4O15 film.

Fabrication and Evaluation of One-Axis Oriented Lead Zirconate Titanate Films Using Metal–Oxide Nanosheet Interface Layer

“…[20][21][22][23][24][25][26] It has recently been reported that the ns-CNs can be utilized as a component for forming a crystalline buffer layer suitable for (001)/(100) epitaxial growth of PZT crystals, as well as the preferential crystal growth of other perovskite-type dielectrics such as bismuth layer-structured dielectrics (BLSD), i.e., SrBi 4 Ti 4 O 15 and SrTiO 3 . 22,23,27) We expect that the present method based on the ns-CN buffer layer will enable the preferential crystal growth of PZT films even on a ubiquitous substrate with random crystal orientation, which will be accomplished by a lowered processing temperature.…”

Effects of Hexagonal BaTiO3 Addition on Textured BaTiO3 Thick Films Prepared by Screen Printing

“…[3][4][5][6] Controlling the orientation of polycrystalline ferroelectric materials can enhance their properties. Oriented ferroelectric films prepared by chemical solution deposition (CSD), 7,8) sputtering, 9) and pulsed laser deposition (PLD), 10,11) have been investigated. However, complex processes are needed to obtain oriented film patterns.…”

Dielectric Property of Silicate-Doped CaBi4Ti4O15Thin Films

“…19,20) Stable TCC values were also obtained for one-axis-oriented CaBi 4 Ti 4 O 15 and SrBi 4 Ti 4 O 15 films with a c-axis orientation normal to the substrate surface and an in-plane random orientation, which were deposited on platinized silicon wafers buffered by a (100)LaNiO 3 layer [i.e., (001)BLSD == (100)LaNiO 3 / (111)Pt/TiO 2 /(100)Si] by chemical solution deposition (CSD). [21][22][23] These results suggest that the dielectric permittivity and its temperature dependence are mainly determined by the out-of-plane nature of the dielectric films and are independent of the in-plane crystal orientation. The authors expected that the material synthesis on versatile and economical silicon wafers would contribute to actual manufacturing more than that on (001)SrTiO 3 single crystals.…”