US5155657A
Expired / Lapsed
US
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High area capacitor formation using material dependent etching
Assignee: International Business Machines Corp
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Filing: 1991-10-31
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Granted: 1992-10-13
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Expires: 2011-10-31
Abstract
Abstract The invention provides a capacitor having increased capacitance comprising one or more main vertical trenches and one or more lateral trenches extending off the main vertical trench. The capacitor has alternating first and second regions, preferably silicon and non-silicon regions (for example, alternating silicon and germanium or alternating silicon and carbon regions). The etch characteristics of the alternating regions are utilized to selectively etch lateral trenches thereby increasing the surface area and capacitance of the capacitor. A method of fabricating the capacitors is also provided.
Inventors
- 👤 Gottlieb S. Oehrlein
- 👤 Vishnubhai V. Patel
- 👤 Alfred Grill
- 👤 Rodney T. Hodgson
- 👤 Gary W. Rubloff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:14
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10B12/30; H10B12/31; H10B12/318; H10D; H10D1/00; H10D1/01; H10D1/041; H10D1/042; H10D1/60; H10D1/62; H10D1/66; H10D1/665; H10D1/68; H10D1/692; H10D1/711; H10D1/714; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
75 words
A capacitor comprising: one or more main vertical trenches and one or more lateral trenches extending off each of said one or more main vertical trenches, said capacitor having alternating first and second regions of material through which said one or more main vertical trenches extend, said first region of material having different etch characteristics from said second region of material, and at least one of said first and second regions comprising a non-silicon region.
Claim 2
Dependent Claim
75 words
A capacitor comprising: one or more main vertical trenches and one or more lateral trenches extending off each of said one or more main vertical trenches, said capacitor having alternating first and second regions of material through which said one or more main vertical trenches extend, said first region of material having different etch characteristics from said second region of material, and at least one of said first and second regions comprising a non-silicon region.
Claim 3
Dependent Claim
21 words
The capacitor of claim 1 wherein said first and second regions of material comprise a silicon region and a non-silicon region.
Claim 4
Dependent Claim
12 words
The capacitor of claim 2 wherein said capacitor comprises a trench capacitor.
Claim 5
Dependent Claim
12 words
The capacitor of claim 2 wherein said capacitor comprises a stacked capacitor.
Claim 6
Dependent Claim
18 words
The capacitor of claim 4 wherein said alternating regions comprise alternating layers of said silicon and non-silicon regions.
Claim 7
Dependent Claim
10 words
The capacitor of claim 2 wherein said non-silicon comprises germanium.
Claim 8
Dependent Claim
12 words
The capacitor of claim 2 wherein said non-silicon comprises a germanium/silicon alloy.
Claim 9
Dependent Claim
15 words
The capacitor of claim 2 wherein said silicon region of said capacitor comprises doped silicon.
Claim 10
Dependent Claim
12 words
The capacitor of claim 8 wherein said doped silicon comprises p-doped silicon.
Claim 11
Dependent Claim
12 words
The capacitor of claim 8 wherein said doped silicon comprises n-doped silicon.
Claim 12
Dependent Claim
14 words
The capacitor of claim 9 wherein said p-doped silicon comprises silicon doped with boron.
Claim 13
Dependent Claim
16 words
The capacitor of claim 10 wherein said n-doped silicon comprises silicon doped with arsenic or phosphorus.
Claim 14
Dependent Claim
78 words
A capacitor comprising: one or more main vertical trenches and one or more lateral trenches extending off each of said one or more main vertical trenches, said capacitor having been formed from alternating first and second regions of material through which said one or more main vertical trenches extend, said first region of material having different etch characteristics from said second region of material, and at least one of said first and second regions comprising a non-silicon region.
Claim 15
Dependent Claim
78 words
A capacitor comprising: one or more main vertical trenches and one or more lateral trenches extending off each of said one or more main vertical trenches, said capacitor having been formed from alternating first and second regions of material through which said one or more main vertical trenches extend, said first region of material having different etch characteristics from said second region of material, and at least one of said first and second regions comprising a non-silicon region.
Claim 16
Dependent Claim
10 words
The capacitor of claim 13 wherein said non-silicon comprises carbon.
Claim 17
Independent Claim
113 words
A method of increasing the capacitance of a capacitor which comprises: forming a capacitor having alternating first and second regions of material, said first region of material having different etch characteristics from said second region of material, and at least one of said first and second regions comprising a non-silicon region; etching one or more main vertical trenches in said capacitor by etching vertically through said first and second regions of material; and etching one or more lateral trenches off said one or more main vertical trenches by selectively laterally etching one of said first and second regions, thereby increasing surface area of said capacitor so as to increase capacitance of said capacitor.
Claim 18
Independent Claim
113 words
A method of increasing the capacitance of a capacitor which comprises: forming a capacitor having alternating first and second regions of material, said first region of material having different etch characteristics from said second region of material, and at least one of said first and second regions comprising a non-silicon region; etching one or more main vertical trenches in said capacitor by etching vertically through said first and second regions of material; and etching one or more lateral trenches off said one or more main vertical trenches by selectively laterally etching one of said first and second regions, thereby increasing surface area of said capacitor so as to increase capacitance of said capacitor.
Claim 19
Dependent Claim
21 words
The method of claim 15 wherein said first and second regions of material comprise a silicon region and a non-silicon region.
Claim 20
Dependent Claim
19 words
The method of claim 15 wherein said etching of said one or more main vertical trenches comprises dry etching.
Claim 21
Dependent Claim
21 words
The method of claim 17 wherein said dry etching of said one or more main vertical trenches comprises anisotropic dry etching.
Claim 22
Dependent Claim
14 words
The method of claim 18 wherein said anisotropic dry etching comprises reactive ion etching.
Claim 23
Dependent Claim
17 words
The method of claim 19 wherein said reactive ion etching comprises reactive ion etching without sidewall passivation.
Claim 24
Dependent Claim
19 words
The method of claim 15 wherein said etching of said one or more main vertical trenches comprises wet etching.
Claim 25
Dependent Claim
18 words
The method of claim 15 wherein said etching of said one or more lateral trenches comprises dry etching.
Claim 26
Dependent Claim
20 words
The method of claim 22 wherein said dry etching of said one or more lateral trenches comprises isotropic dry etching.
Claim 27
Dependent Claim
18 words
The method of claim 15 wherein said etching of said one or more lateral trenches comprises wet etching.
Claim 28
Dependent Claim
15 words
The method of claim 15 wherein said lateral etch comprises etching with SF 6 .
Claim 29
Dependent Claim
17 words
The method of claim 15 wherein said lateral etch comprises etching with CF 4 /H 2 .
Claim 30
Dependent Claim
13 words
The method of claim 15 wherein said lateral etch comprises etching with oxygen.
Claim 31
Dependent Claim
28 words
The method of claim 15 wherein said etching of said one or more main vertical trenches is simultaneous with said etching of said one or more lateral trenches.
Claim 32
Dependent Claim
129 words
A capacitor stacked upon a wafer surface of a semiconductor device, said capacitor comprising: one or more multilayered cells; and one or more main vertical trenches surrounding each of said one or more multilayered cells; wherein each of said one or more multilayered cells comprises a vertical region of doped polysilicon and one or more lateral trenches extending off one of said surrounding main vertical trenches between layers of doped polysilicon, each of said one or more multilayered cells having been formed from alternating first and second regions of material through which said one or more main vertical trenches extend, said first region of material having different etch characteristics from said second region of material, and at least one of said first and second regions comprising a non-silicon region.
Claim 33
Dependent Claim
129 words
A capacitor stacked upon a wafer surface of a semiconductor device, said capacitor comprising: one or more multilayered cells; and one or more main vertical trenches surrounding each of said one or more multilayered cells; wherein each of said one or more multilayered cells comprises a vertical region of doped polysilicon and one or more lateral trenches extending off one of said surrounding main vertical trenches between layers of doped polysilicon, each of said one or more multilayered cells having been formed from alternating first and second regions of material through which said one or more main vertical trenches extend, said first region of material having different etch characteristics from said second region of material, and at least one of said first and second regions comprising a non-silicon region.
Claim 34
Dependent Claim
16 words
The capacitor of claim 29 wherein said layers of doped polysilicon have a dielectric coating thereon.
Claim 35
Dependent Claim
19 words
The capacitor of claim 30 wherein said dielectric coating is formed by oxidation of said layers of doped polysilicon.
Claim 36
Dependent Claim
19 words
The capacitor of claim 30 wherein said dielectric coating is formed by chemical vapor deposition of an oxide layer.
Claim 37
Dependent Claim
30 words
The capacitor of claim 29 further including a top layer of doped polysilicon overlying said one or more multilayered cells and extending into said one or more main vertical trenches.
Claim 38
Dependent Claim
51 words
A semiconductor device comprising the capacitor of claim 31 wherein each of said one or more multilayered cells of said capacitor overlies an oxide layer which overlies a transistor device, said transistor device having associated lines, and wherein said top layer of doped polysilicon functions as an electrode for said capacitor.
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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) | 1995-10-13 | 1996-04-13 | 1996-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-13 | 2000-04-13 | 2000-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-13 | 2004-04-13 | 2004-10-13 | $7700.00 | Window Closed / Lapsed |