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US5572052A
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Electronic device using zirconate titanate and barium titanate ferroelectrics in insulating layer
Assignee: Mitsubishi Electric Corp
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Filing: 1995-01-19
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Granted: 1996-11-05
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Expires: 2015-01-19
Abstract
Abstract In an electronic device using lead zirconate titanate (PZT) or lanthanum lead zirconate titanate (PLZT) as the main insulating material, a PZT film or a PLZT film is formed on a sub-insulating layer consisting essentially of lead titanate, lanthanum lead titanate, barium titanate, strontium titanate, barium strontium titanate, lead zirconate, or lanthanum lead zirconate. In an MIS structure, a semiconductor, the sub-insulating layer, the PZT film and metal are deposited in order. In a capacitor, the sub-insulating layer and the PZT film are sandwiched between a pair of electrodes. The sub-insulating layer improves crystallinity of PZT or PLZT, and the dielectric constant. An oxide of Pb, La, Zr or Ti can be added as the sub-insulating layer in order to further suppress current leakage.
Inventors
- 👤 Keiichiro Kashihara
- 👤 Tomonori Okudaira
- 👤 Hiromi Itoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:32
CPC Classifications
H; H10; H10B; H10B53/00; H10D; H10D1/00; H10D1/60; H10D1/62; H10D1/66; H10D30/00; H10D30/60; H10D30/701
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
122 words
An electronic device including a MIS structure, wherein said MIS structure comprises: a silicon layer, a sub-insulating layer formed directly on said silicon layer by CVD or sputtering, and consisting essentially of at least a compound selected from the group consisting of lead titanate, lanthanum lead titanate, barium titanate, strontium titanate, barium strontium titanate, lead zirconate, and lanthanum lead zirconate, a main insulating layer formed directly on said sub-insulating layer by CVD or sputtering, and consisting essentially of zirconate titanate, and a layer formed on said main insulating layer, and consisting essentially of a conductor, wherein said main insulating layer has a perovskite type crystal structure, and exhibits ferroelectricity at ambient temperature, and wherein said sub-insulating layer consists essentially of barium titanate.
Claim 2
Dependent Claim
122 words
An electronic device including a MIS structure, wherein said MIS structure comprises: a silicon layer, a sub-insulating layer formed directly on said silicon layer by CVD or sputtering, and consisting essentially of at least a compound selected from the group consisting of lead titanate, lanthanum lead titanate, barium titanate, strontium titanate, barium strontium titanate, lead zirconate, and lanthanum lead zirconate, a main insulating layer formed directly on said sub-insulating layer by CVD or sputtering, and consisting essentially of zirconate titanate, and a layer formed on said main insulating layer, and consisting essentially of a conductor, wherein said main insulating layer has a perovskite type crystal structure, and exhibits ferroelectricity at ambient temperature, and wherein said sub-insulating layer consists essentially of barium titanate.
Claim 3
Dependent Claim
155 words
An electronic device including a MIS structure, wherein said MIS structure comprises: a silicon layer, a film formed directly on said silicon layer, and consisting essentially of a material selected from the group consisting of silicon oxide, silicon nitride, nitride oxide, TiO 2 and Ta 2 O 5 , a sub-insulating layer formed directly on said film by CVD or sputtering, and consisting essentially of at least a compound selected from the group consisting of lead titanate, lanthanum lead titanate, barium titanate, strontium titanate, barium strontium titanate, lead zirconate, and lanthanum lead zirconate, a main insulating layer formed directly on said sub-insulating layer by CVD or sputtering, and consisting essentially of zirconate titanate and, a layer formed on said main insulating layer, and consisting essentially of a conductor, wherein said main insulating layer has a perovskite type crystal structure, and exhibits ferroelectricity at ambient temperature, and wherein said sub-insulating layer consists essentially of barium titanate.
Claim 4
Dependent Claim
155 words
An electronic device including a MIS structure, wherein said MIS structure comprises: a silicon layer, a film formed directly on said silicon layer, and consisting essentially of a material selected from the group consisting of silicon oxide, silicon nitride, nitride oxide, TiO 2 and Ta 2 O 5 , a sub-insulating layer formed directly on said film by CVD or sputtering, and consisting essentially of at least a compound selected from the group consisting of lead titanate, lanthanum lead titanate, barium titanate, strontium titanate, barium strontium titanate, lead zirconate, and lanthanum lead zirconate, a main insulating layer formed directly on said sub-insulating layer by CVD or sputtering, and consisting essentially of zirconate titanate and, a layer formed on said main insulating layer, and consisting essentially of a conductor, wherein said main insulating layer has a perovskite type crystal structure, and exhibits ferroelectricity at ambient temperature, and wherein said sub-insulating layer consists essentially of barium titanate.
Claim 5
Dependent Claim
128 words
An electronic device including a capacitor structure, wherein said capacitor structure comprises: a first electrode consisting essentially of noble metal, a sub-insulating layer formed directly on said first electrode by CVD or sputtering, and consisting essentially of at least a compound selected from the group consisting of lead titanate, lanthanum lead titanate, barium titanate, strontium titanate, barium strontium titanate, lead zirconate, and lanthanum lead zirconate, a main insulating layer formed directly on said sub-insulating layer by CVD or sputtering, and consisting essentially of zirconate titanate, and a second electrode formed on said main insulating layer, and consisting essentially of a conductor, wherein said main insulating layer has a perovskite type crystal structure, and exhibits ferroelectricity at ambient temperature, and wherein said sub-insulating layer consists essentially of barium titanate.
Claim 6
Dependent Claim
128 words
An electronic device including a capacitor structure, wherein said capacitor structure comprises: a first electrode consisting essentially of noble metal, a sub-insulating layer formed directly on said first electrode by CVD or sputtering, and consisting essentially of at least a compound selected from the group consisting of lead titanate, lanthanum lead titanate, barium titanate, strontium titanate, barium strontium titanate, lead zirconate, and lanthanum lead zirconate, a main insulating layer formed directly on said sub-insulating layer by CVD or sputtering, and consisting essentially of zirconate titanate, and a second electrode formed on said main insulating layer, and consisting essentially of a conductor, wherein said main insulating layer has a perovskite type crystal structure, and exhibits ferroelectricity at ambient temperature, and wherein said sub-insulating layer consists essentially of barium titanate.
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