US5521115A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making double grid substrate plate DRAM cell array
Assignee: International Business Machines Corp
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Filing: 1994-09-30
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Granted: 1996-05-28
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Expires: 2014-09-30
Abstract
Abstract A high density substrate plate trench DRAM cell memory device and process are described in which a buried region is formed adjacent to deep trench capacitors such that the substrate region of DRAM transfer FETs can be electrically isolated from other FETs on a semiconductor substrate. The buried region is contacted along its perimeter by a reach through region to complete the isolation. The combined regions reduce charge loss due to better control of device parasitics.
Inventors
- 👤 Jong W. Park
- 👤 Steven H. Voldman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:49
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/30; H10B12/37; H10B12/01; H10B12/02; H10B12/03; H10B12/038
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
169 words
The method of making a dynamic random access memory device comprising the steps of: providing a semiconductor substrate of a first conductivity type; forming a buried region of second conductivity type over at least a portion of the area of said substrate; forming an array of trenches in a matrix pattern in the top surface of said substrate, each trench penetrating into said substrate and substantially into said buried region; forming a dielectric layer of a predetermined thickness on the inside surfaces of said trenches and filling said trenches with a conductive electrode material; ion implanting and diffusing around the perimeter of said array of trenches a diffused region of said second conductivity type having a depth so as to physically and electrically isolate a portion of the substrate within the matrix pattern above said buried region; and forming within the isolated portion of the matrix pattern a plurality of semiconductor devices for coupling signals to and from said conductive electrode material within at least some of said trenches.
Claim 2
Independent Claim
169 words
The method of making a dynamic random access memory device comprising the steps of: providing a semiconductor substrate of a first conductivity type; forming a buried region of second conductivity type over at least a portion of the area of said substrate; forming an array of trenches in a matrix pattern in the top surface of said substrate, each trench penetrating into said substrate and substantially into said buried region; forming a dielectric layer of a predetermined thickness on the inside surfaces of said trenches and filling said trenches with a conductive electrode material; ion implanting and diffusing around the perimeter of said array of trenches a diffused region of said second conductivity type having a depth so as to physically and electrically isolate a portion of the substrate within the matrix pattern above said buried region; and forming within the isolated portion of the matrix pattern a plurality of semiconductor devices for coupling signals to and from said conductive electrode material within at least some of said trenches.
Claim 3
Dependent Claim
53 words
The method of making a dynamic random access memory device of claim 1 wherein the step of forming a dielectric layer on the inside surfaces of said trenches includes a step of forming a second dielectric layer thicker than said first dielectric layer to form a collar at the top of said trenches.
Claim 4
Dependent Claim
27 words
The method of making a dynamic random access memory device of claim 1 wherein the source of dopant material used to form the buried region is N-type.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-05-28 | 1999-11-27 | 2000-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-05-28 | 2003-11-27 | 2004-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-05-28 | 2007-11-27 | 2008-05-28 | $7700.00 | Window Closed / Lapsed |