US5882973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming an integrated circuit having transistors of dissimilarly graded junction profiles
Assignee: Advanced Micro Devices Inc
•
Filing: 1997-01-27
•
Granted: 1999-03-16
•
Expires: 2017-01-27
Abstract
Abstract An integrated circuit is provided having a plurality of transistors either NMOS transistors, or PMOS transistors, or both NMOS and PMOS transistors. The transistors are formed having dissimilarly sized spacers. The spacers can be made larger in lateral areas on transistors designated as lower performing transistors than smaller spacers used on transistors which are higher performing. The dissimilarly sized spacers produce correspondingly sized lightly doped drain (LDD) areas. Accordingly, the present integrated circuit includes on a single monolithic substrate both high and low performance transistors based upon formation of dissimilarly sized spacers at sidewall surfaces of select transistor gate conductors.
Inventors
- 👤 Mark I. Gardner
- 👤 Fred N. Hause
- 👤 H. Jim. Fulford, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:25
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0147; H10D84/0165; H10D84/0184; H10D84/02; H10D84/03; H10D84/038
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
140 words
A method for forming an integrated circuit, comprising: providing a first channel area and a second channel area spaced from each other within a semiconductor substrate; patterning a first gate conductor and a second gate conductor a dielectric distance over respective first and second channel areas; forming an etch stop layer upon the first and second gate conductors and upon junctions configured within the semiconductor substrate between the first and second channel areas; forming, from a first material, first spacers extending a first lateral distance from the first and second gate conductors; forming, from a second material different from the first material, second spacers extending a second lateral distance from the first and second gate conductors; and selectively removing the second spacers from a region adjacent the second gate conductor while retaining the second spacers adjacent the first gate conductor.
Claim 2
Independent Claim
140 words
A method for forming an integrated circuit, comprising: providing a first channel area and a second channel area spaced from each other within a semiconductor substrate; patterning a first gate conductor and a second gate conductor a dielectric distance over respective first and second channel areas; forming an etch stop layer upon the first and second gate conductors and upon junctions configured within the semiconductor substrate between the first and second channel areas; forming, from a first material, first spacers extending a first lateral distance from the first and second gate conductors; forming, from a second material different from the first material, second spacers extending a second lateral distance from the first and second gate conductors; and selectively removing the second spacers from a region adjacent the second gate conductor while retaining the second spacers adjacent the first gate conductor.
Claim 3
Dependent Claim
22 words
The method as recited in claim 1, further comprising forming isolation structures between the first gate conductor and the second gate conductor.
Claim 4
Dependent Claim
58 words
The method as recited in claim 1, wherein said forming the first spacers comprises: depositing the first material upon the first and second gate conductors; and selectively removing the first material from substantially horizontal surfaces of the etch stop layer such that the first material remains proximate only to sidewall surfaces of the first and second gate conductors.
Claim 5
Dependent Claim
42 words
The method as recited in claim 3, wherein said selectively removing the first material comprises anisotropically etching the first material layer at a faster rate along horizontal surfaces of the etch stop layer than along vertical surfaces of the etch stop layer.
Claim 6
Dependent Claim
62 words
The method as recited in claim 1, wherein said forming the second spacers comprises: depositing the second material upon the first and second gate conductors; and selectively removing the second material from substantially horizontal surfaces of the etch stop layer and the first spacers such that the second material remains proximate only to sidewall surfaces of the first and second gate conductors.
Claim 7
Dependent Claim
47 words
The method as recited in claim 5, wherein said selectively removing the second material comprises anisotropically etching the second material layer at a faster rate along horizontal surfaces of the etch stop layer than along vertical surfaces of the etch stop layer and of the first spacers.
Claim 8
Dependent Claim
31 words
The method as recited in claim 1, wherein the etch stop layer comprises a material selected from the group consisting of thermally grown silicon dioxide and chemical vapor deposited silicon dioxide.
Claim 9
Dependent Claim
20 words
The method as recited in claim 1, wherein the etch stop layer comprises a lower layer and an upper layer.
Claim 10
Dependent Claim
44 words
The method as recited in claim 1, wherein the etch stop layer comprises: a lower layer comprising a material selected from the group consisting of thermally grown oxide and chemical vapor deposited silicon dioxide; and an upper layer comprising chemical vapor deposited silicon nitride.
Claim 11
Dependent Claim
26 words
The method as recited in claim 1, wherein the first spacer comprises a material selected from the group consisting of silicon dioxide, polysilicon, and silicon nitride.
Claim 12
Dependent Claim
26 words
The method as recited in claim 1, wherein the second spacer comprises a material selected from the group consisting of silicon dioxide, polysilicon, and silicon nitride.
Claim 13
Dependent Claim
54 words
The method as recited in claim 1, wherein selective removal of the second spacers comprises: forming a masking layer on the first gate conductor; performing an etch selective to the second material such that the first spacer is retained adjacent the second gate conductor; and removing the masking layer from the first gate conductor.
Claim 14
Dependent Claim
24 words
The method as recited in claim 1, further comprising forming lightly doped drains adjacent the gate conductors prior to forming the etch stop layer.
Claim 15
Dependent Claim
26 words
The method as recited in claim 1, further comprising forming source and drain areas following removal of the second spacers from adjacent the second gate conductor.
Claim 16
Dependent Claim
67 words
The method as recited in claim 14, further comprising: removing the etch stop layer from above the gate conductors and the source and drain regions; depositing a refractory metal across the gate conductors, the spacers, and the source and drain areas; heating the refractory metal to form a metal silicide on the gate conductors and the source and drain regions; and removing unreacted metal from the spacers.
Claim 17
Dependent Claim
74 words
The method as recited in claim 1, wherein selectively removing the second spacers from the region adjacent the second gate conductor while retaining the second spacers adjacent the first gate conductor comprises removing only a portion of said second spacers from adjacent said second gate conductor such that said second spacers extend a third lateral distance from said second gate conductor, and wherein said third lateral distance is less than said second lateral distance.
References Cited (Backward Citations)
US5276346A
Cited
US5164801A
Cited
US5254866A
Cited
US5436482A
Cited
US5115288A
Cited
US5274261A
Cited
US5329482A
Cited
US5716866A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-03-15 | 2002-09-14 | 2003-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-15 | 2006-09-14 | 2007-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-15 | 2010-09-14 | 2011-03-16 | $7700.00 | Window Closed / Lapsed |