Patent US5024964A successfully refreshed from Google Patents.
US5024964A
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Method of making ferroelectric memory devices
Assignee: Ramtron International Corp
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Filing: 1985-10-31
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Granted: 1991-06-18
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Expires: 2005-10-31
Abstract
Abstract A monolithic semiconductor integrated circuit-ferroelectric device is disclosed together with the method of manufacturing same. The ferroelectric device preferably consists of a layer of stable ferroelectric potassium nitrate disposed between electrical contacts positioned on opposite surfaces of the ferroelectric layer. The ferroelectric layer has a thickness of less than 110 microns, and preferably falling within a range of from 100 Angstrom units to 25,000 Angstrom units. The process of manufacturing the monolithic structure is multi-stepped and is particularly adapted for fabricating a potassium nitrate ferroelectric memory on a semiconductor integrated circuit.
Inventors
- 👤 George A. Rohrer
- 👤 Larry D. McMillin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:55
CPC Classifications
H; H01; H01G; H01G7/00; H01G7/02; C; C23; C23C; C23C14/00; C23C14/06; H01G7/025
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
71 words
A method of fabricating a monolithic ferroelectric memory device coupled to an integrated circuit comprising the steps of: forming first layer interconnects coupled to the integrated circuit; depositing a non-semiconductor dielectric and forming interconnect and bonding pad vias therein; depositing a conductive layer and forming a bottom electrode; applying a ferroelectric layer; depositing a conductive layer and forming a top electrode; and applying conductive material to the bonding and interconnect pads.
Claim 2
Independent Claim
71 words
A method of fabricating a monolithic ferroelectric memory device coupled to an integrated circuit comprising the steps of: forming first layer interconnects coupled to the integrated circuit; depositing a non-semiconductor dielectric and forming interconnect and bonding pad vias therein; depositing a conductive layer and forming a bottom electrode; applying a ferroelectric layer; depositing a conductive layer and forming a top electrode; and applying conductive material to the bonding and interconnect pads.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein said ferroelectric layer substantially comprises Phase III potassium nitrate.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein said first layer interconnections are composed of doped polysilicon.
Claim 5
Dependent Claim
24 words
The method of claim 1 wherein said non-semiconductor dielectric is selected from the group consisting of low temperature glass, silicon nitride and sputtered dielectrics.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein said first layer interconnections are composed of a metal.
Claim 7
Dependent Claim
18 words
The method of claim 1 wherein said ferroelectric KNO 3 layer has a thickness less than 110 microns.
Claim 8
Dependent Claim
26 words
The method of claim 1 wherein said ferroelectric KNO 3 layer has a thickness within a range of from 100 Angstrom units to 5,000 Angstrom units.
Claim 9
Dependent Claim
33 words
The method of claim 1 wherein said ferroelectric potassium nitrate layer has a thickness of less than 1 micron and comprises Phase III potassium nitrate which is stable at standard temperature and pressure.
Claim 10
Dependent Claim
33 words
The method of claim 1 wherein the top electrode is formed by defining a top conductive layer by standard photoresist techniques and back sputtering said metal layer until the top electrode is defined.
Claim 11
Dependent Claim
19 words
The method of claim 9 wherein the top conductive layer is partially etched before subjecting it to back sputtering.
Claim 12
Dependent Claim
30 words
The methd of claim 2 wherein both said ferroelectric layer and said top electrode are deposited under a single pumpdown to prevent the ferroelectric layer from being exposed to moisture.
Claim 13
Dependent Claim
12 words
The method of claim 1 wherein said top electrode is partially etched.
Claim 14
Independent Claim
76 words
A method of fabricating a monolithic ferroelectric memory device coupled to an integrated circuit comprising the steps of: forming first layer interconnects coupled to the integrated circuit; depositing a non-semiconductor dielectric and establishing interconnect and bond pad vias therein; depositing a conductive layer and forming a bottom electrode; depositing a second non-semiconductor dielectric and forming vias therein; depositing a conductive layer and forming a top electrode; and applying conductive material to the bonding and interconnect pads.
Claim 15
Independent Claim
76 words
A method of fabricating a monolithic ferroelectric memory device coupled to an integrated circuit comprising the steps of: forming first layer interconnects coupled to the integrated circuit; depositing a non-semiconductor dielectric and establishing interconnect and bond pad vias therein; depositing a conductive layer and forming a bottom electrode; depositing a second non-semiconductor dielectric and forming vias therein; depositing a conductive layer and forming a top electrode; and applying conductive material to the bonding and interconnect pads.
Claim 16
Dependent Claim
15 words
The method of claim 13 wherein said ferroelectric layer substantially comprises Phase III potassium nitrate.
Claim 17
Dependent Claim
15 words
The method of claim 13 wherein said first layer interconnections are composed of doped polysilicon.
Claim 18
Dependent Claim
24 words
The method of claim 13 wherein said non-semiconductor dielectric is selected from the group consisting of low temperature glass, silicon nitride and sputtered dielectrics.
Claim 19
Dependent Claim
15 words
The method of claim 13 wherein said first layer interconnections are composed of a metal.
Claim 20
Dependent Claim
30 words
The method of claim 14 wherein both said ferroelectric layer and said top electrode are deposited under a single pumpdown to prevent the ferroelectric layer from being exposed to moisture.
Claim 21
Independent Claim
99 words
A method of fabricating a monolithic ferroelectric memory device coupled to an integrated circuit comprising the steps of: forming first layer interconnects coupled to the integrated circuit; depositing a non-semiconductor dielectric and establishing interconnect and bonding pad vias therein; depositing a conductive layer and forming a bottom electrode; depositing a second non-conductive dielectric and forming vias therein; applying a ferroelectric layer; depositing a conductive layer and forming a top electrode; depositing a top non-semiconductor dielectric layer uniformly; removing said top non-semiconductor dielectric layer from the bonding and interconnect pads; and applying conductive material to the bonding and interconnect pads.
Claim 22
Independent Claim
99 words
A method of fabricating a monolithic ferroelectric memory device coupled to an integrated circuit comprising the steps of: forming first layer interconnects coupled to the integrated circuit; depositing a non-semiconductor dielectric and establishing interconnect and bonding pad vias therein; depositing a conductive layer and forming a bottom electrode; depositing a second non-conductive dielectric and forming vias therein; applying a ferroelectric layer; depositing a conductive layer and forming a top electrode; depositing a top non-semiconductor dielectric layer uniformly; removing said top non-semiconductor dielectric layer from the bonding and interconnect pads; and applying conductive material to the bonding and interconnect pads.
Claim 23
Dependent Claim
15 words
The method of claim 19 wherein said ferroelectric layer substantially comprises Phase III potassium nitrate.
Claim 24
Dependent Claim
15 words
The method of claim 19 wherein said first layer interconnections are composed of doped polysilicon.
Claim 25
Dependent Claim
24 words
The method of claim 19 wherein said non-semiconductor dielectric is selected from the group consisting of low temperature glass, silicon nitrate and sputtered dielectrics.
Claim 26
Dependent Claim
15 words
The method of claim 19 wherein said first layer interconnections are composed of a metal.
Claim 27
Dependent Claim
30 words
The method of claim 20, wherein both said ferroelectric layer and said top electrode are deposited under a single pumpdown to prevent the ferroelectric layer from being exposed to moisture.
References Cited (Backward Citations)
US3405440A
Cited
US3571915A
Cited
US3483477A
Cited
US3939292A
Cited
US4195355A
Cited
US3728674A
Cited
US3874922A
Cited
US3986478A
Cited
US3996551A
Cited
US4013489A
Cited
US4149302A
Cited
US4149301A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-06-17 | 1994-12-17 | 1995-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-17 | 1998-12-17 | 1999-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-17 | 2002-12-17 | 2003-06-18 | $7700.00 | Window Closed / Lapsed |