Patent US5656524A successfully refreshed from Google Patents.
US5656524A
Expired / Lapsed
US
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Method of forming a polysilicon resistor using an oxide, nitride stack
Assignee: Texas Instruments Inc
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Filing: 1995-06-07
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Granted: 1997-08-12
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Expires: 2015-06-07
Abstract
Abstract A polysilicon resistor (40) includes a field oxide layer (12) and a polysilicon layer (20) that covers a portion of field oxide layer (12). The polysilicon layer (20) possesses a predetermined electrical resistance value. Nitride/oxide stack (42) covers a predetermined portion of the polysilicon layer (20) and forms at least one exposed location of polysilicon layer (20) on which not to implant a dopant to achieve a predetermined resistance value. Silicide layer (34) covers exposed location.
Inventors
- 👤 Robert H. Eklund
- 👤 Douglas A. Prinslow
- 👤 David B. Scott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:05
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/40; H10D1/47; H10P; H10P32/00; H10P32/30; H10P32/302
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
141 words
A method for forming a polysilicon resistor on a field oxide region, comprising the steps of: depositing a layer of polysilicon over said field oxide region; patterning and etching said polysilicon layer to form a polysilicon structure over a portion of said field oxide region; forming an oxide layer over said polysilicon structure and said field oxide region; forming a nitride layer over said oxide layer; etching said nitride layer to remove said nitride layer except on the portion of the oxide layer on the sidewalls of said polysilicon structure; forming a pattern on said oxide layer to define the body of the polysilicon resistor; etching said oxide layer to remove said oxide layer except under said pattern exposing a portion of said polysilicon structure; removing said pattern; and forming a silicide layer on said exposed portion of the polysilicon structure.
Claim 2
Independent Claim
141 words
A method for forming a polysilicon resistor on a field oxide region, comprising the steps of: depositing a layer of polysilicon over said field oxide region; patterning and etching said polysilicon layer to form a polysilicon structure over a portion of said field oxide region; forming an oxide layer over said polysilicon structure and said field oxide region; forming a nitride layer over said oxide layer; etching said nitride layer to remove said nitride layer except on the portion of the oxide layer on the sidewalls of said polysilicon structure; forming a pattern on said oxide layer to define the body of the polysilicon resistor; etching said oxide layer to remove said oxide layer except under said pattern exposing a portion of said polysilicon structure; removing said pattern; and forming a silicide layer on said exposed portion of the polysilicon structure.
Claim 3
Dependent Claim
37 words
The method of claim 1, further comprising the step of implanting a dopant into said polysilicon layer to adjust the sheet resistance of the polysilicon resistor prior to the step of patterning and etching the polysilicon layer.
Claim 4
Dependent Claim
31 words
The method of claim 2, wherein said step of implanting the polysilicon layer comprises implanting arsenic at a dose of about 6.0E15 ion/cm 2 and an energy of about 150 KeV.
Claim 5
Dependent Claim
24 words
The method of claim 2, further comprising the step of annealing the polysilicon layer to diffuse and activate the dopant throughout the polysilicon layer.
Claim 6
Dependent Claim
39 words
The method of claim 1, further comprising the step of implanting a source/drain dopant through said oxide layer into said polysilicon structure after said step of forming a pattern and prior to said step of etching said oxide layer.
Claim 7
Independent Claim
150 words
A method for forming a polysilicon resistor on a field oxide region, comprising the steps of: depositing a layer of polysilicon over said field oxide region; patterning and etching said polysilicon layer to form a polysilicon structure over a portion of said field oxide region; forming an oxide layer over said polysilicon structure; forming a nitride layer over said oxide layer; forming a pattern on said nitride layer to define the body of the polysilicon resistor; etching said nitride layer to remove said nitride layer except under said pattern and on the portion of the oxide layer on the sidewalls of said polysilicon structure; removing said pattern; etching said oxide layer to remove said oxide layer except on the sidewalls of said polysilicon layer and under said etched nitride layer exposing a portion of said polysilicon structure; and forming a silicide layer on said exposed portion of the polysilicon structure.
Claim 8
Independent Claim
150 words
A method for forming a polysilicon resistor on a field oxide region, comprising the steps of: depositing a layer of polysilicon over said field oxide region; patterning and etching said polysilicon layer to form a polysilicon structure over a portion of said field oxide region; forming an oxide layer over said polysilicon structure; forming a nitride layer over said oxide layer; forming a pattern on said nitride layer to define the body of the polysilicon resistor; etching said nitride layer to remove said nitride layer except under said pattern and on the portion of the oxide layer on the sidewalls of said polysilicon structure; removing said pattern; etching said oxide layer to remove said oxide layer except on the sidewalls of said polysilicon layer and under said etched nitride layer exposing a portion of said polysilicon structure; and forming a silicide layer on said exposed portion of the polysilicon structure.
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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) | 2000-08-11 | 2001-02-10 | 2001-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-11 | 2005-02-10 | 2005-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-11 | 2009-02-10 | 2009-08-12 | $7700.00 | Window Closed / Lapsed |