US5153813A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High area capacitor formation using dry etching
Assignee: International Business Machines Corp
•
Filing: 1991-10-31
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Granted: 1992-10-06
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Expires: 2011-10-31
Abstract
Abstract The invention provides a method of increasing the capacitance of a capacitor which comprises forming a capacitor having a main vertical trench and one or more lateral trenches extending off the main vertical trench. The capacitor has alternating first and second silicon regions, for example n-doped and p-doped silicon regions. After a main vertical trench is dry etched through the first and second silicon regions, the etch characteristics of the alternating first and second silicon regions are utilized to selectively dry etch lateral trenches, thereby increasing the surface area of the capacitor and the capacitance of the capacitor. Capacitors produced by this method are also provided.
Inventors
- 👤 Gottlieb S. Oehrlein
- 👤 Gary W. Rubloff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:45
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/01; H10D1/041; H10D1/042; H10D1/045; H10D1/047; H10D1/60; H10D1/62; H10D1/66; H10D1/665; H10D1/68; H10D1/692; H10D1/711; H10D1/714
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
93 words
A method of increasing the capacitance of a capacitor which comprises: forming a capacitor having alternating first and second silicon regions, said first silicon region having different etch characteristics from said second silicon region; dry etching a main vertical trench in said capacitor by etching vertically through said first and said second silicon regions; and dry etching lateral trenches off said main vertical trench by selectively laterally dry etching one of said first and said second silicon regions, thereby increasing surface area of said capacitor so as to increase capacitance of said capacitor.
Claim 2
Independent Claim
93 words
A method of increasing the capacitance of a capacitor which comprises: forming a capacitor having alternating first and second silicon regions, said first silicon region having different etch characteristics from said second silicon region; dry etching a main vertical trench in said capacitor by etching vertically through said first and said second silicon regions; and dry etching lateral trenches off said main vertical trench by selectively laterally dry etching one of said first and said second silicon regions, thereby increasing surface area of said capacitor so as to increase capacitance of said capacitor.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said capacitor comprises a trench capacitor.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein said capacitor comprises a stacked capacitor.
Claim 5
Dependent Claim
19 words
The method of claim 3 wherein said alternating regions comprise alternating layers of said first and second silicon regions.
Claim 6
Dependent Claim
23 words
The method of claim 1 wherein at least one of said first and said second silicon regions of said capacitor comprises doped silicon.
Claim 7
Dependent Claim
12 words
The method of claim 5 wherein said doped silicon comprises p-doped silicon.
Claim 8
Dependent Claim
21 words
The method of claim 6 wherein said first silicon region comprises p-doped silicon and said second silicon region comprises n-doped silicon.
Claim 9
Dependent Claim
25 words
The method of claim 6 wherein said first silicon region comprises p-doped silicon and said second silicon region comprises p-doped silicon which is also n-doped.
Claim 10
Dependent Claim
14 words
The method of claim 6 wherein said p-doped silicon comprises silicon doped with boron.
Claim 11
Dependent Claim
12 words
The method of claim 5 wherein said doped silicon comprises n-doped silicon.
Claim 12
Dependent Claim
21 words
The method of claim 10 wherein said first silicon region comprises n-doped silicon and said second silicon region comprises undoped silicon.
Claim 13
Dependent Claim
16 words
The method of claim 10 wherein said n-doped silicon comprises silicon doped with arsenic or phosphorus.
Claim 14
Dependent Claim
16 words
The method of claim 5 wherein said doped silicon comprises p-doped silicon which is also n-doped.
Claim 15
Dependent Claim
19 words
The method of claim 5 wherein formation of said doped silicon comprises in situ doping during chemical vapor deposition.
Claim 16
Dependent Claim
20 words
The method of claim 5 wherein formation of said doped silicon comprises ion implantation of a dopant into said silicon.
Claim 17
Dependent Claim
20 words
The method of claim 1 wherein said one of said first and second silicon regions of said capacitor comprises n-doped.
Claim 18
Dependent Claim
17 words
The method of claim 1 wherein said etching of said main vertical trench comprises anisotropic dry etching.
Claim 19
Dependent Claim
14 words
The method of claim 17 wherein said anisotropic dry etching comprises reactive ion etching.
Claim 20
Dependent Claim
17 words
The method of claim 18 wherein said reactive ion etching comprises reactive ion etching without sidewall passivation.
Claim 21
Dependent Claim
16 words
The method of claim 1 wherein said etching of said lateral trenches comprises isotropic dry etching.
Claim 22
Dependent Claim
22 words
The method of claim 1 wherein said etching of said main vertical trench is simultaneous with said etching of said lateral trenches.
Claim 23
Dependent Claim
86 words
A capacitor having increased capacitance produced by: forming alternating first and second silicon regions, said first silicon region having different etch characteristics from said second silicon region; dry etching a main vertical trench in said capacitor by etching vertically through said first and said second silicon regions; and dry etching lateral trenches off said main vertical trench by selectively laterally dry etching one of said first and said second silicon regions, thereby increasing surface area of said capacitor so as to increase capacitance of said capacitor.
Claim 24
Dependent Claim
86 words
A capacitor having increased capacitance produced by: forming alternating first and second silicon regions, said first silicon region having different etch characteristics from said second silicon region; dry etching a main vertical trench in said capacitor by etching vertically through said first and said second silicon regions; and dry etching lateral trenches off said main vertical trench by selectively laterally dry etching one of said first and said second silicon regions, thereby increasing surface area of said capacitor so as to increase capacitance of said capacitor.
Claim 25
Dependent Claim
21 words
The capacitor of claim 22 wherein said first silicon region comprises p-doped silicon and said second silicon region comprises n-doped silicon.
Claim 26
Dependent Claim
25 words
The capacitor of claim 22 wherein said first silicon region comprises p-doped silicon and said second silicon region comprises p-doped silicon which is also n-doped.
Claim 27
Dependent Claim
21 words
The capacitor of claim 22 wherein said first silicon region comprises n-doped silicon and said second silicon region comprises undoped silicon.
References Cited (Backward Citations)
JPS59191333A
Cited
US4475982A
Cited
JPS60173871A
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JPS60176265A
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JPS60224261A
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US4853348A
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US4601778A
Cited
US5102817A
Cited
US4943344A
Cited
US4906590A
Cited
US5095346A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-10-06 | 1996-04-06 | 1996-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-06 | 2000-04-06 | 2000-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-06 | 2004-04-06 | 2004-10-06 | $7700.00 | Window Closed / Lapsed |