US5899725A
Expired / Lapsed
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Method of forming a hemispherical grained silicon on refractory metal nitride
Assignee: Round Rock Research LLC
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Filing: 1997-01-08
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Granted: 1999-05-04
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Expires: 2017-01-08
Abstract
Abstract Disclosed is a method of growing hemispherical grained silicon (HSG silicon) over a conductive seed layer. In a preferred embodiment, a contact window is etched in an insulating layer to expose a circuit node, such as an active area of a substrate or a contact plug leading to an active area. A layer of titanium nitride is deposited over the insulating layer and into the contact window. The titanium nitride (TiN) serves as the seed layer for HSG silicon growth to follow. Polysilicon is deposited and grows around nucleation sites on the TiN surface. The TiN provides both electrical and mechanical support for the HSG silicon. Additionally, as TiN is an effective diffusion barrier, the HSG silicon may be heavily doped without undue risk of dopant diffusion to the active area.
Inventors
- 👤 Steven T. Harshfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:28
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/069; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10D1/711; H10D1/712; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10W20/0698
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
71 words
A method of forming a plate of a capacitor in an integrated circuit, the method comprising the steps of: etching a contact window through an insulating layer of the integrated circuit; depositing a metal nitride layer over the insulating layer and into the contact window, the metal nitride layer electrically contacting an active area of an underlying substrate; and growing a hemispherical grained silicon layer directly on the metal nitride layer.
Claim 2
Independent Claim
71 words
A method of forming a plate of a capacitor in an integrated circuit, the method comprising the steps of: etching a contact window through an insulating layer of the integrated circuit; depositing a metal nitride layer over the insulating layer and into the contact window, the metal nitride layer electrically contacting an active area of an underlying substrate; and growing a hemispherical grained silicon layer directly on the metal nitride layer.
Claim 3
Dependent Claim
16 words
The method of claim 1, wherein the metal nitride layer comprises a refractory metal nitride layer.
Claim 4
Dependent Claim
16 words
The method of claim 2, wherein the refractory metal nitride layer comprises a titanium nitride layer.
Claim 5
Dependent Claim
24 words
The method of claim 3, wherein the titanium nitride layer is deposited to a thickness range of between about 50 Å and 500 Å.
Claim 6
Dependent Claim
16 words
The method of claim 4, wherein the titanium nitride depositing step comprises a chemical vapor deposition.
Claim 7
Dependent Claim
17 words
The method of claim 5, wherein the chemical vapor deposition comprises a metal organic chemical vapor deposition.
Claim 8
Dependent Claim
18 words
The method of claim 6, wherein the metal organic chemical vapor deposition comprises decomposing a tetrakisdimethylamidotitanium organic precursor.
Claim 9
Dependent Claim
38 words
The method of claim 7, wherein the metal organic chemical vapor deposition comprises depositing the titanium nitride at a temperature range between about 300° C. and 500° C., and a pressure range between about 0.1 and 2.0 Torr.
Claim 10
Dependent Claim
15 words
The method of claim 8, wherein the titanium nitride layer directly contacts the active area.
Claim 11
Dependent Claim
16 words
The method of claim 3, further comprising the step of thermal annealing the titanium nitride layer.
Claim 12
Dependent Claim
36 words
The method of claim 10, wherein the anneal step comprises heating the titanium nitride layer to a temperature between about 600° C. and 900° C. for a time interval between about 10 minutes and 30 minutes.
Claim 13
Dependent Claim
41 words
The method of claim 11, wherein the anneal step comprises heating the titanium nitride layer to a temperature between about 650° C. and 800° C. in a predominantly nitrogen environment for a time interval between about 20 seconds and 30 seconds.
Claim 14
Dependent Claim
17 words
The method of claim 3, further comprising the step of hydrogen plasma annealing the titanium nitride layer.
Claim 15
Dependent Claim
25 words
The method of claim 13, wherein the hydrogen plasma anneal comprises flowing both a hydrogen plasma and a nitrogen plasma over the titanium nitride layer.
Claim 16
Dependent Claim
35 words
The method of claim 1, further comprising the step of heavily doping the hemispherical grained silicon layer with an electrically activating dopant, and wherein the metal nitride layer forms a diffusion barrier to the dopants.
Claim 17
Dependent Claim
21 words
The method of claim 15, wherein the dopant comprises a phosphorous dopant derived from a solid source under oxygen assisted diffusion.
Claim 18
Dependent Claim
15 words
The method of claim 16, wherein the solid source comprises P 2 O 5 .
Claim 19
Dependent Claim
17 words
The method of claim 1, wherein the hemispherical grained silicon growth step comprises a chemical vapor deposition.
Claim 20
Dependent Claim
16 words
The method of claim 18, wherein the chemical vapor deposition comprises a low pressure chemical deposition.
Claim 21
Dependent Claim
40 words
The method of claim 19, wherein the low pressure chemical vapor deposition comprises a decomposition of SiH 4 at a temperature range between about 540° C. and 560° C., and a pressure range between about 10 mTorr and 300 mTorr.
Claim 22
Independent Claim
63 words
A method of forming a layer of texturized polysilicon, the method comprising the steps of: forming a metal nitride seed layer having a top surface, the seed layer comprising a plurality of nucleation sites on the top surface; and depositing a layer of polysilicon over the seed layer, the polysilicon preferentially nucleating around the nucleation sites to form a plurality of polysilicon nodules.
Claim 23
Independent Claim
63 words
A method of forming a layer of texturized polysilicon, the method comprising the steps of: forming a metal nitride seed layer having a top surface, the seed layer comprising a plurality of nucleation sites on the top surface; and depositing a layer of polysilicon over the seed layer, the polysilicon preferentially nucleating around the nucleation sites to form a plurality of polysilicon nodules.
Claim 24
Dependent Claim
14 words
The method of claim 21, wherein the seed layer comprises a refractory metal nitride.
Claim 25
Dependent Claim
14 words
The method of claim 22, wherein the refractory metal nitride comprises a titanium nitride.
Claim 26
Dependent Claim
24 words
The method of claim 23, wherein the seed layer forming step comprises depositing a titanium nitride layer over a substrate by chemical vapor deposition.
Claim 27
Dependent Claim
42 words
The method of claim 24, wherein the chemical vapor deposition comprises a metal organic chemical vapor deposition utilizing a tetrakisdimethylamidotitanium precursor at a temperature range between about 300° C. and 500° C., and a pressure range between about 0.1 and 2.0 Torr.
Claim 28
Dependent Claim
12 words
The method of claim 21, further comprising a post-deposition thermal annealing step.
Claim 29
Dependent Claim
11 words
The method of claim 21, further comprising a hydrogen plasma anneal.
Claim 30
Dependent Claim
17 words
The method of claim 21, wherein the polysilicon depositing step comprises a low pressure chemical vapor deposition.
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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) | 2002-05-03 | 2002-11-02 | 2003-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-03 | 2006-11-02 | 2007-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-03 | 2010-11-02 | 2011-05-04 | $7700.00 | Window Closed / Lapsed |