Patent US5499207A successfully refreshed from Google Patents.
US5499207A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor memory device having improved isolation between electrodes, and process for fabricating the same
Assignee: PS4 Luxco SARL
•
Filing: 1994-07-28
•
Granted: 1996-03-12
•
Expires: 2014-07-28
Abstract
Abstract With recent decreases in the size of semiconductor memories, isolation problems typically arise during fabrication of a capacitor for a high-capacity semiconductor memory device. To overcome this, arrangements are provided to improve the isolation between capacitor elements even if those elements are extremely close together. For example, if a material such as platinum is used as a capacitor bottom electrode, a thin layer of titanium oxide can be deposited before forming the platinum, to provide a structure in which the titanium oxide is on the bottom portion of the trench. A high-dielectric-constant insulator is then formed over that structure by the Chemical Vapor Deposition. The high-dielectric-constant insulator has a composition which satisfies the stoichiometric composition over the platinum and which has more titanium atoms than those of the stoichiometric composition on the trench bottom. The resulting non-stoichiometric composition layer formed on the trench bottom has a low dielectric constant and a high insulation to maintain electric insulation between adjoining bottom capacitor electrodes. Because of a low crystallization, moreover, a layer having a planarized morphology is formed.
Inventors
- 👤 Hiroshi Miki
- 👤 Yuzuru Ohji
- 👤 Shinichi Tachi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:18
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/682; H10B; H10B12/00; H10B12/30; H10B12/31; H10B12/318; H10D1/692; Y; Y10; Y10S; Y10S438/00; Y10S438/974
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
56 words
A semiconductor memory device having a plurality of capacitors arranged in parallel, wherein each capacitor include at least one electrode, said memory device comprising: a first insulator arranged between the electrodes of said capacitors; and a second insulator acting as dielectrics of said capacitors, wherein said first insulator is a modified portion of said second insulator.
Claim 2
Dependent Claim
56 words
A semiconductor memory device having a plurality of capacitors arranged in parallel, wherein each capacitor include at least one electrode, said memory device comprising: a first insulator arranged between the electrodes of said capacitors; and a second insulator acting as dielectrics of said capacitors, wherein said first insulator is a modified portion of said second insulator.
Claim 3
Dependent Claim
36 words
A semiconductor memory device as set forth in claim 1, characterized in that said first insulator is interposed between the electrodes of said capacitors and a third insulator for insulating said capacitors from other electric circuits.
Claim 4
Dependent Claim
22 words
A semiconductor memory device as set forth in claim 1, characterized in that said second insulator is formed by Chemical Vapor Deposition.
Claim 5
Dependent Claim
43 words
A-semiconductor memory device as set forth in claim 1, characterized in that the dielectric constant of said second insulator at a portion contacting with said first insulator is no more than 10% of the dielectric constant of said second insulator over said electrode.
Claim 6
Dependent Claim
32 words
A semiconductor memory device as set forth in claim 1, characterized in that said first insulator is composed mainly of an oxide of any one of Ta, Nb, Ti, Zr and Hf.
Claim 7
Dependent Claim
24 words
A semiconductor memory device as set forth in claim 1, characterized in that said first insulator is formed by Chemical Vapor Deposition or Sol-Gel.
Claim 8
Dependent Claim
29 words
A semiconductor memory device as set forth in claim 1, characterized in that said at least one electrode of each capacitor is comprised mainly of platinum, palladium or nickel.
Claim 9
Dependent Claim
25 words
A semiconductor memory device as set forth in claim 1, wherein said second insulator is formed on a side wall of one of said electrodes.
Claim 10
Dependent Claim
49 words
A semiconductor memory device according to claim 1, wherein the first insulator is formed relative to the electrodes of the capacitors and relative to the second insulator so that characteristics of the first insulator can be selectively changed in a self-aligned manner without deteriorating characteristics of the second insulator.
Claim 11
Dependent Claim
16 words
A semiconductor memory device as set forth in claim 1, wherein said first insulator is planarized.
Claim 12
Dependent Claim
34 words
A semiconductor memory device as set forth in claim 10, wherein said first insulator is interposed between the electrodes of said capacitors and a third insulator for insulating said capacitors from other electric circuits.
Claim 13
Dependent Claim
20 words
A semiconductor memory device as set forth in claim 10, wherein said second insulator is formed by Chemical Vapor Deposition.
Claim 14
Dependent Claim
31 words
A semiconductor memory device as set forth in claim 10, wherein the dielectric constant of said first insulator is not more than 10% of the dielectric constant of said second insulator.
Claim 15
Dependent Claim
30 words
A semiconductor memory device as set forth in claim 10, wherein said first insulator is composed mainly of an oxide of any one of Ta, Nb, Ti, Zr, and Hf.
Claim 16
Dependent Claim
17 words
A semiconductor memory device as set forth in claim wherein said first insulator is formed by Sol-Gel.
Claim 17
Dependent Claim
27 words
A semiconductor memory device as set forth in claim 10, wherein said at least one electrode of each capacitor is comprised mainly of platinum, palladium or nickel.
Claim 18
Dependent Claim
121 words
A semiconductor memory device comprising: an insulator formed over a semiconductor active layer, which active layer includes a device for driving a capacitor; a bottom electrode of the capacitor formed over a predetermined region of said insulator and having a predetermined shape; a crystalline insulator formed continuously over an exposed surface of said insulator and said bottom electrode; and an upper electrode of the capacitor formed over said crystalline insulator, wherein the portion of said insulator, over which said bottom electrode is not formed, has a modified surface, and wherein the crystallinity and dielectric constant of said crystalline insulator formed over said modified surface are lower than the crystallinity and dielectric constant of said crystalline insulator formed over said bottom electrode.
Claim 19
Dependent Claim
121 words
A semiconductor memory device comprising: an insulator formed over a semiconductor active layer, which active layer includes a device for driving a capacitor; a bottom electrode of the capacitor formed over a predetermined region of said insulator and having a predetermined shape; a crystalline insulator formed continuously over an exposed surface of said insulator and said bottom electrode; and an upper electrode of the capacitor formed over said crystalline insulator, wherein the portion of said insulator, over which said bottom electrode is not formed, has a modified surface, and wherein the crystallinity and dielectric constant of said crystalline insulator formed over said modified surface are lower than the crystallinity and dielectric constant of said crystalline insulator formed over said bottom electrode.
Claim 20
Dependent Claim
22 words
A semiconductor memory device as set forth in claim 17, characterized in that said crystalline insulator contains barium titanate or lead titanate.
Claim 21
Dependent Claim
45 words
A semiconductor memory device as set forth in claim 17, characterized in that said modified surface of said insulator is made of silicon dioxide, and in that said modified surface has a smaller oxidation number than portions of the silicon dioxide that are not modified.
Claim 22
Dependent Claim
20 words
A semiconductor memory device as set forth in claim 17, characterized in that said modified surface is an ion-implanted layer.
Claim 23
Dependent Claim
29 words
A semiconductor memory device as set forth in claim 17, characterized in that said modified surface contains more silicon than portions of the insulator other than said modified surface.
Claim 24
Dependent Claim
39 words
A semiconductor memory device as set forth in claim 17, characterized in that the insulator having said modified surface is made of silicon dioxide, and in that said modified surface is formed by reducing the amount of silicon dioxide.
Claim 25
Dependent Claim
29 words
A semiconductor memory device as set forth in claim 17, characterized in that said semiconductor active layer is a semiconductor substrate on which metal oxide semiconductor transistors are formed.
Claim 26
Dependent Claim
41 words
A semiconductor memory device as set forth in claim 17, wherein the dielectric constant of said crystalline insulator formed over said modified surface is not more than 10% of the dielectric constant of said crystalline insulator formed over said bottom electrode.
Claim 27
Dependent Claim
29 words
A-semiconductor memory device as set forth in claim 17, wherein said crystalline insulator is composed mainly of an oxide of any one of Ta, Nb, Ti, Zr, and Hf.
Claim 28
Dependent Claim
22 words
A semiconductor memory device as set forth in claim 17, wherein said crystalline insulator is formed by Chemical Vapor Deposition or Sol-Gel.
Claim 29
Dependent Claim
27 words
A semiconductor memory device as set forth in claim 17, wherein said at least one electrode of said capacitor is comprised mainly of platinum, palladium or nickel.
Claim 30
Dependent Claim
164 words
A semiconductor memory device comprising: an active device layer; a first insulator formed over said active device layer; a second insulator having a low dielectric constant formed over said first insulator; a plurality of bottom capacitor electrodes formed over said second insulator, said bottom capacitor electrodes being spaced apart from one another on said second insulator; a high dielectric constant layer formed over said bottom capacitor electrodes and over portions of said second insulator located between said bottom capacitor electrodes, wherein said second insulator and said high dielectric constant layer include materials that will react with one another at said portions of said second insulator located between said bottom capacitor electrodes to form a modified structure having a low dielectric constant and a high breakdown voltage between the bottom capacitor electrodes; and a top capacitor electrode formed over said high dielectric constant layer over said bottom capacitor electrodes, and also formed over said portions of said modified structure located between said bottom capacitor electrodes.
Claim 31
Dependent Claim
164 words
A semiconductor memory device comprising: an active device layer; a first insulator formed over said active device layer; a second insulator having a low dielectric constant formed over said first insulator; a plurality of bottom capacitor electrodes formed over said second insulator, said bottom capacitor electrodes being spaced apart from one another on said second insulator; a high dielectric constant layer formed over said bottom capacitor electrodes and over portions of said second insulator located between said bottom capacitor electrodes, wherein said second insulator and said high dielectric constant layer include materials that will react with one another at said portions of said second insulator located between said bottom capacitor electrodes to form a modified structure having a low dielectric constant and a high breakdown voltage between the bottom capacitor electrodes; and a top capacitor electrode formed over said high dielectric constant layer over said bottom capacitor electrodes, and also formed over said portions of said modified structure located between said bottom capacitor electrodes.
Claim 32
Dependent Claim
24 words
A semiconductor memory device according to claim 28, wherein said second insulator comprises titanium dioxide, and wherein said high dielectric constant layer comprises PZT.
Claim 33
Dependent Claim
16 words
A semiconductor memory device according to claim 28, wherein said modified structure is a pyrochlore structure.
Claim 34
Dependent Claim
73 words
A semiconductor memory device having a plurality of capacitors arranged in parallel, wherein each capacitor includes at least one electrode, said memory device comprising: a first insulator arranged between the electrodes of said capacitors, a second insulator acting as dielectrics of said capacitors, wherein said first insulator and said second insulator are formed at the same time, and wherein said first insulator has a smaller dielectric constant than that of said second insulator.
Claim 35
Dependent Claim
73 words
A semiconductor memory device having a plurality of capacitors arranged in parallel, wherein each capacitor includes at least one electrode, said memory device comprising: a first insulator arranged between the electrodes of said capacitors, a second insulator acting as dielectrics of said capacitors, wherein said first insulator and said second insulator are formed at the same time, and wherein said first insulator has a smaller dielectric constant than that of said second insulator.
Claim 36
Dependent Claim
49 words
A semiconductor memory device according to claim 31, wherein the first insulator is formed relative to the electrodes of the capacitors and relative to the second insulator so that characteristics of the first insulator can be selectively changed in a self-aligned manner without deteriorating characteristics of the second insulator.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-03-12 | 1999-09-11 | 2000-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-12 | 2003-09-11 | 2004-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-12 | 2007-09-11 | 2008-03-12 | $7700.00 | Window Closed / Lapsed |