US5757612A
Expired / Lapsed
US
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Structure and fabrication method for non-planar memory elements
Assignee: International Business Machines Corp
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Filing: 1996-04-23
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Granted: 1998-05-26
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Expires: 2016-04-23
Abstract
Abstract Structures for memory cell applications, including capacitors for DRAM and ferroelectric memory cells from FRAM, whose method of manufacture consists of depositing a ferroelectric or high-epsilon dielectric material to completely fill a cavity whose geometrical width is the sole determinant of the thickness of the electrically active portion of the ferroelectric or high-epsilon dielectric layer in the final device. In the preferred embodiment, the cavity into which the dielectric is deposited is defined by the gap between the plate and stack electrodes which are deposited and patterned in a through-mask plating step prior to the dielectric deposition.
Inventors
- 👤 Raul Edmundo Acosta
- 👤 James Hartfiel Comfort
- 👤 Alfred Grill
- 👤 David Edward Kotecki
- 👤 Katherine Lynn Saenger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:17
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/682
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
142 words
An electrical device comprising: a substrate; a first conductive region formed in said substrate of a first conductive material; a first dielectric layer formed above said substrate, said first dielectric layer having a contact via above a portion of said first conductive region, said contact via being filled with a second conductive material; a planar layer formed above said first dielectric layer, said planar layer containing separated first and second electrodes of a third and fourth conductive material, respectively; said first and second electrodes being deposited to define a gap whose width is equal to the spacing between the first and second electrode sidewalls; said first electrode surrounding said second electrode; said second electrode being positioned over said contact via and isolated from the first electrode; and a layer of second dielectric material filling the gap between the first and second electrodes.
Claim 2
Dependent Claim
142 words
An electrical device comprising: a substrate; a first conductive region formed in said substrate of a first conductive material; a first dielectric layer formed above said substrate, said first dielectric layer having a contact via above a portion of said first conductive region, said contact via being filled with a second conductive material; a planar layer formed above said first dielectric layer, said planar layer containing separated first and second electrodes of a third and fourth conductive material, respectively; said first and second electrodes being deposited to define a gap whose width is equal to the spacing between the first and second electrode sidewalls; said first electrode surrounding said second electrode; said second electrode being positioned over said contact via and isolated from the first electrode; and a layer of second dielectric material filling the gap between the first and second electrodes.
Claim 3
Dependent Claim
18 words
The electrical device of claim 1 wherein said third and fourth conductive materials are the same or different.
Claim 4
Dependent Claim
35 words
The electrical device of claim 1 wherein said first and second electrodes are made from a multilayer of two or more electrically conductive materials, said layers being the same or different material for both electrodes.
Claim 5
Dependent Claim
26 words
The electrical device of claim 1 further including a third dielectric layer on or above the top surface of said first, or second or both electrodes.
Claim 6
Dependent Claim
24 words
The electrical device of claim 1 wherein one or more additional dielectric layers are placed between the first dielectric layer and the first electrode.
Claim 7
Dependent Claim
18 words
The electrical device of claim 1 wherein the second conductive material substantially consists of doped polysilicon or tungsten.
Claim 8
Dependent Claim
41 words
The electrical device of claim 1 further including a layer of a fifth conducting material, which is both a barrier to oxygen diffusion and a barrier to silicon or tungsten diffusion, located at the top surface of the second conductive material.
Claim 9
Dependent Claim
26 words
The electrical device of claim 1 wherein said second conductive material is both a barrier to oxygen diffusion and a barrier to silicon or tungsten diffusion.
Claim 10
Dependent Claim
38 words
The electrical device of claim 1 wherein said second dielectric material is selected from the group consisting of ferroelectric, paraelectric, perovskites, pyrochlores, relaxors, layered perovskites, or any material with a dielectric constant greater than or equal to 20.
Claim 11
Dependent Claim
73 words
The electrical device of claim 9 wherein said second dielectric material is selected from the group consisting of Ta 2 O 5 , (Ba,Sr)TiO 3 (BST or BSTO), BaTiO 3 , SrTiO 3 , PbZr 1-x Ti x O 3 (PZT), PbZrO 3 , Pb 1-x La x TiO 3 (PLT), Pb 1-x La x (Zr y Ti 1-y ) 1-x/4 O 3 (PLZT) , and SrBi 2 Ta 2 O 9 (SBT).
Claim 12
Dependent Claim
53 words
The electrical device of claim 1 wherein said third and fourth conductive materials are selected from the group consisting of noble metals, alloys of noble metals with noble or non-noble metals, metals whose oxides are conducting, electrically conducting oxides, electrically conducting nitrides, electrically conducting silicides, and electrically conductive materials whose oxides are insulating.
Claim 13
Dependent Claim
46 words
The electrical device of claim 11 wherein said third and fourth conductive materials are selected from the group consisting of Au, Pt, Pd, Ir, Rh, Ru, Mo, RuO 2 , IrO 2 , Re 2 O 3 , TiN, TaN, TaSiN, TaSi 2 , and WN.
Claim 14
Dependent Claim
36 words
A capacitor having any of the cross-sectional structures described in claims 1, 4, 5, 7 or 8, where the sidewall gap filled with the second dielectric material has the form of a circle or hollow cross.
Claim 15
Dependent Claim
40 words
A capacitor having any of the cross-sectional structures described in claim 13, where the gap or cavity filled with the second dielectric material has a width in the range 300-1200 Å and a height between 500 Å and 3 μm.
Claim 16
Dependent Claim
20 words
A capacitive memory element for DRAM having any of the structures described in claims 1, 4, 5, 7 or 8.
Claim 17
Dependent Claim
22 words
A ferroelectric memory element for NVRAM or FRAM having any of the structures described in claims 1, 4, 5, 7 or 8.
Claim 18
Dependent Claim
16 words
A semiconductor device containing any of the structures of claims 1, 4, 5, 7 or 8.
References Cited (Backward Citations)
US5389566A
Cited
US5408130A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-05-25 | 2001-11-24 | 2002-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-25 | 2005-11-24 | 2006-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-25 | 2009-11-24 | 2010-05-26 | $7700.00 | Window Closed / Lapsed |