Hetero-Epitaxial PbZr0. 48Ti0. 52O3 Capacitors with Oxide Electrodes

Mitsuo SUGA  Masahiko HIRATANI  Choichiro OKAZAKI  Masanari KOGUCHI  Hiroshi KAKIBAYASHI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E81-C   No.4   pp.523-527
Publication Date: 1998/04/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Advanced Memory Devices Using High-Dielectric-Constant and Ferroelectric Thin Films)
Category: 
Keyword: 
epitaxy,  TEM,  PZT,  SrRuO3,  SrTiO3,  

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Summary: 
Two types of hetero-epitaxial PbZr0. 48Ti0. 52O3 (PZT) capacitors were fabricated by pulsed laser deposition (PLD). One has an Au/PZT/SrRuO3(SRO)/SrTiO3(STO) structure with remanent polarization (Pr) of 32. 1 µC/cm2. The other has an Au/PZT/La-doped STO (La: STO) structure with Pr of 9. 6 to 13. 5 µC/cm2. X-ray diffraction patterns show that only the (00l) planes of the PZT and SRO are parallel to the substrate surface for the PZT/SRO/STO structure, however, a (111) plane of the PZT is observed, in addition to the (00l) planes, for the PZT/La: STO structure. High resolution-transmission electron microscope (HR-TEM) images show that the PZT/SRO interface is clean and coherent. However, spherical shape contrast with radius about 5 nm is observed at the PZT/La: STO interface. Diffusion of La and/or the contaminated surface of the La: STO substrate is thought to cause the differences in the PZT orientations and the interfaces, affecting the electrical characteristics of the capacitors.