Ferroelectric nonvolatile memory and oxide multi-layered structure
AssigneeSony Corporation
InventorMasayuki Suzuki
Life of this patent
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Abstract
A ferroelectric memory includes a silicon substrate having a buffer layer on the substrate and a conductive oxide thin film on the buffer layer. A bismuth based layered ferroelectric oxide thin film is formed on the conductive oxide and a further conductive layer is formed on the ferroelectric layer. In one embodiment, the buffer layer is substantially lattice matched with the silicon substrate, the conductive oxide thin film is substantially lattice matched with the buffer layer, and the bismuth-based layered ferroelectric oxide thin film is substantially lattice matched with the conductive oxide thin film. Additionally, the invention includes the use of a superlattice structure for the ferroelectric layer.
Claims104
A ferroelectric nonvolatile memory comprising:
- a silicon substrate;
- a buffer layer comprised of an oxide on said silicon substrate, said oxide selected from the group consisting of magnesium oxide, cerium oxide, .alpha.-alumina, yttrium stabilized zirconia and magnesium aluminate spinel;
- a conductive oxide thin film on said buffer layer, said conductive oxide thin film selected from the group consisting of SrRuO.sub.3 and Sr.sub.2 RuO.sub.4 ;
- a bismuth-based layered ferroelectric oxide thin film on said conductive oxide thin film;
- and
- a conductive layer on said bismuth-based layered ferroelectric oxide thin film, wherein said buffer layer is substantially lattice matched with said silicon substrate, said conductive oxide thin film is substantially lattice matched with said buffer layer, and said bismuth-based layered ferroelectric oxide thin film is substantially lattice matched with said conductive oxide thin film, wherein said buffer layer, said conductive oxide thin film and said bismuth-based layered ferroelectric oxide thin film are epitaxially grown on said silicon substrate.
A ferroelectric nonvolatile memory comprising:
- a silicon substrate;
- a buffer layer made of an oxide on said silicon substrate, said oxide selected from the group consisting of magnesium oxide, cerium oxide, .alpha.-alumina, yttrium stabilized zirconia and magnesium aluminate spinel;
- a conductive oxide thin film on said buffer layer, said conductive oxide thin film selected from the group consisting of SrRuO.sub.3 and Sr.sub.2 RuO.sub.4 ;
- an oxide superlattice including at least a ferroelectric oxide thin film on said conductive oxide thin film;
- and
- a conductive layer on said oxide superlattice, wherein said buffer layer, said conductive oxide thin film and said oxide superlattice are epitaxially grown on said silicon substrate.
A ferroelectric nonvolatile memory comprising:
- a silicon substrate;
- a buffer layer made of an oxide on said silicon substrate, said oxide selected from the group consisting of magnesium oxide, cerium oxide, .alpha.-alumina, yttrium stabilized zirconia and magnesium aluminate spinel;
- a bismuth-based layered ferroelectric oxide thin film on said buffer layer;
- and
- a first conductive oxide thin film and a second conductive oxide thin film on said buffer layer at opposite sides of said bismuth-based layered ferroelectric oxide thin film and in contact with sidewalls of said bismuth-based layered ferroelectric oxide thin film, wherein said buffer layer, said bismuth-based layered ferroelectric oxide thin film and said first and second conductive oxide thin films are epitaxially grown on said silicon substrate, said conductive oxide thin films selected from the group consisting of SrRuO.sub.3 and Sr.sub.2 RuO.sub.4.
The ferroelectric nonvolatile memory according to claims, wherein said first conductive oxide thin film and said second conductive oxide thin film are made of SrRuO.sub.3.
A ferroelectric nonvolatile memory comprising:
- a silicon substrate;
- a buffer layer made of an oxide on said silicon substrate, said oxide selected from the group consisting of magnesium oxide, cerium oxide, .alpha.-alumina, yttrium stabilized zirconia and magnesium aluminate spinel;
- an oxide superlattice including at least a ferroelectric oxide thin film on said buffer layer;
- and
- a first conductive oxide thin film and a second conductive oxide thin film on said buffer layer at opposite sides of said oxide superlattice and in contact with sidewalls of said oxide superlattice, wherein said buffer layer, said oxide superlattice, said first conductive oxide thin film and said second conductive oxide thin film are epitaxially grown on said silicon substrate, said conductive oxide thin films selected from the group consisting of SrRuO.sub.3 and Sr.sub.2 RuO.sub.4.
An oxide multi-layered structure comprising:
- a silicon substrate;
- a buffer layer made of an oxide on said silicon substrate, said oxide selected from the group consisting of cerium oxide and magnesium aluminate spinel;
- and
- a conductive oxide thin film on said buffer layer, said conductive oxide thin film selected from the group consisting of SrRuO.sub.3 and Sr.sub.2 RuO.sub.4.
Dependencies are inferred from the claim text.