Preparation of PZT Film on (100)Pt/(100) MgO Substrate by CVD and Its Properties

Abstract

PZT thin films were epitaxially grown on (100)Pt/ (100)MgO substrates by CVD under partial oxygen pressure (PO2) from 0.96 to 8.4Torr. The crystal struc ture and microstructure of the films were almost the same as those prepared on MgO substrates irrespective of PO2. However, for films deposited below 1.6Torr of PO2, the existence of PbPt5-7 phase was ascertained by XRD measurement, and the electric leakage between top and bottom electrodes was observed. The X-ray pole figure measurement showed that this PbPt5-7 was epitaxially related to the deposited PZT thin film and the (100)Pt/(100)MgO substrate. The relative dielec tric constant, r, of epitaxially grown Pb(Zr0.5Ti0.5)O3 films was about 300, lower than that of non-oriented film. This phenomenon can be elucidated by the fact that the calculated r of PZT crystals along the c-axis is lower than that perpendicular to the c-axis.

Crystal Structure Analysis of Epitaxial BiFeO3–BiCoO3 Solid Solution Films Grown by Metalorganic Chemical Vapor Deposition

“…Figures 3(c (rhombohedral/monoclinic) symmetry to tetragonal symmetry was confirmed between x ¼ 0 and 0.33. The estimated maximum strain applied from the substrate by the misfit strain at the deposition temperature was lower than the reported strain for the BiCoO 3 preparation, as reported by Belik et al 8,12) Therefore, these other factors must be taken into account: 1) two-dimensional stress for film growth is different from three-dimensional stress for bulk growth; 2) the excess BiFeO 3 composition of the film because BiFeO 3 takes a perovskite structure even under atmospheric pressure; 3) formation energy degradation in the perovskite phase on the substrate having a perovskite structure. A detailed analysis of these factors will be carried out next.…”

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

“…After heating for crystallization for 5 min, the sample was cooled down to Curie temperature to accomplish phase transition of cubicto-tetragonal, where either the [001] or [100] direction of the PZT crystal can align to the substrate surface depending on the degree of thermal stress; the PZT crystals on certain substrates with a larger coefficient of thermal expansion, sub , generally receive a larger thermal stress in compressive mode by the bimetallic effect to align the [001] direction of the PZT crystal, and vice versa. 14,[29][30][31] The crystal orientation determined at Curie temperature was consequently maintained during the cooling process down to room temperature. The sub values of SUS 316L and Inconel 625 are significantly larger than that of silicon wafer, approximately 16 Â 10 À6 , 13 Â 10 À6 , and 2:6 Â 10 À6 K À1 , respectively, which would determine the degree of crystal orientation of the PZT films on the ns-CN interface layer dominantly.…”

Orientation control of barium titanate films using metal oxide nanosheet layer

“…To overcome the negative impact of charge trapping, post-annealing in oxygen atmosphere will be effective to reoxidize the vacancy sites, 48) as well as the complete aging of the precursor gel films followed by their crystallization in air. 44,45) Furthermore, the polar-axis orientation, i.e., the alignment of BaTiO 3 (001) to the substrate surface, would contribute significantly to the enhancement of polarization behavior by applying thermal stress during the crystallization process, 30,31,36,37) although the resulting films in the present research exhibited a nonpolar-axis orientation of BaTiO 3 (100).…”

“…35) The out-of-plane lattice parameters calculated from the peak positions were 0.4013, 0.3990, and 0.3991 nm at the crystallization temperatures of 700, 800, and 900 °C, respectively. The crystal orientation of BaTiO 3 (100) also unfortunately suggests that no polar axis aligned to the substrate surface, which indicates the in-plane orientation of the polar [001] BaTiO 3 axis due to thermal stress 36,37) or tetragonal-to-cubic phase transition caused by the size effect. 38,39) Figure 4 shows SEM images of the fractured surfaces of the BaTiO 3 films fabricated on the ns-CN=Pt=Si substrates at various crystallization temperatures.…”