Patent US6153477A successfully refreshed from Google Patents.
US6153477A
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Ultra short transistor channel length formed using a gate dielectric having a relatively high dielectric constant
Assignee: Advanced Micro Devices Inc
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Filing: 1998-04-14
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Granted: 2000-11-28
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Expires: 2018-04-14
Abstract
Abstract An integrated circuit fabrication process is provided for forming a transistor in which the channel length is mandated by the width of a gate conductor formed upon a gate dielectric having a dielectric constant greater than about 3.8. The thickness of the gate dielectric may be made sufficiently large to serve as a mask during subsequent implantation of impurities into a substrate. The gate conductor and the gate dielectric are first patterned using lithography and an etch step. In one embodiment, a masking layer is then formed across a select portion of the gate conductor and an ensuing source region of the substrate. The uncovered portion of the gate conductor is etched to expose a region of the gate dielectric. A first implant of impurities is forwarded into regions of the substrate not covered by the masking layer to form an LDD area underneath the exposed region of the gate dielectric and a heavily doped drain region laterally adjacent the LDD area. A second implant is then forwarded into the source region to form a heavily doped source region. In another embodiment, the masking layer used to originally pattern the gate conductor is etched to expose portions of the gate conductor. Those exposed portions are then removed. A single implant of impurities is forwarded into the substrate exclusive of underneath the gate conductor. LDD areas are thusly formed beneath portions of the gate dielectric not covered by the gate conductor, and source/drain regions are formed laterally adjacent the LDD areas.
Inventors
- 👤 Mark I. Gardner
- 👤 Mark C. Gilmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:06
CPC Classifications
H; H10; H10P; H10P30/00; H10P30/20; H10P30/202; H10P30/204; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0212; H10D30/0221; H10D30/0223; H10D30/0227; H10D30/0229; H10D30/60; H10D30/601; H10D30/603; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/01342; H10D64/60; H10D64/66; H10D64/68; H10D64/691; H10P30/208; H10P30/21; H10P30/212
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
214 words
A method for forming a transistor, comprising: forming a gate conductor upon a gate dielectric having a dielectric constant greater than approximately 3.8, wherein the gate conductor is interposed between a pair of opposed sidewall surfaces of the gate dielectric and wherein the gate dielectric is arranged upon a portion of a semiconductor substrate; forming a masking layer across a portion of the gate conductor and a source region of the semiconductor substrate, the source region having a lateral boundary aligned to one of the opposed sidewall surfaces, wherein the portion of the gate conductor extends between said one of the opposed sidewall surfaces and a region of the gate conductor positioned between the opposed sidewall surfaces; removing the gate conductor from the gate dielectric exclusive of the portion of the gate conductor and adjacent to the portion of the gate conductor, thereby exposing a selected region of the gate dielectric; forwarding a first impurity distribution into the substrate exclusive of underneath the masking layer to concurrently form a lightly doped drain area within the substrate exclusively underneath the selected region of the gate dielectric and a heavily doped drain region within the substrate laterally adjacent the lightly doped drain area, and removing the masking layer from the source region subsequent to said forwarding.
Claim 2
Independent Claim
214 words
A method for forming a transistor, comprising: forming a gate conductor upon a gate dielectric having a dielectric constant greater than approximately 3.8, wherein the gate conductor is interposed between a pair of opposed sidewall surfaces of the gate dielectric and wherein the gate dielectric is arranged upon a portion of a semiconductor substrate; forming a masking layer across a portion of the gate conductor and a source region of the semiconductor substrate, the source region having a lateral boundary aligned to one of the opposed sidewall surfaces, wherein the portion of the gate conductor extends between said one of the opposed sidewall surfaces and a region of the gate conductor positioned between the opposed sidewall surfaces; removing the gate conductor from the gate dielectric exclusive of the portion of the gate conductor and adjacent to the portion of the gate conductor, thereby exposing a selected region of the gate dielectric; forwarding a first impurity distribution into the substrate exclusive of underneath the masking layer to concurrently form a lightly doped drain area within the substrate exclusively underneath the selected region of the gate dielectric and a heavily doped drain region within the substrate laterally adjacent the lightly doped drain area, and removing the masking layer from the source region subsequent to said forwarding.
Claim 3
Dependent Claim
34 words
The method of claim 1, wherein a first concentration of dopant species within the heavily doped drain region is substantially greater than a second concentration of dopant species within the lightly doped drain area.
Claim 4
Dependent Claim
22 words
The method of claim 1, wherein said forming a masking layer comprises lithographically patterning photoresist across the portion of the gate conductor.
Claim 5
Dependent Claim
26 words
The method of claim 1, further comprising forwarding a second impurity distribution into the source region of the substrate to form a heavily doped source region.
Claim 6
Dependent Claim
19 words
The method of claim 4, wherein the first impurity distribution and the second impurity distribution comprise dissimilar dopant species.
Claim 7
Dependent Claim
35 words
The method of claim 4, wherein the first impurity distribution comprises a first dopant species, and wherein the second impurity distribution comprises a second dopant species having a lower diffusivity than the first dopant species.
Claim 8
Dependent Claim
20 words
The method of claim 6, wherein the heavily doped source region is substantially shallower than the heavily doped drain region.
Claim 9
Dependent Claim
11 words
The method of claim 1, wherein the gate conductor comprises polysilicon.
Claim 10
Dependent Claim
33 words
The method of claim 1, wherein the gate dielectric comprises a material selected from the group consisting of barium strontium titanate, lead lanthanum zirconate titanate, barium zirconate titanate, cerium oxide, and tin oxide.
Claim 11
Independent Claim
135 words
A method for forming a transistor, said method comprising: forming a gate conductor upon a gate dielectric having a dielectric constant greater than approximately 3.8, wherein the gate conductor is interposed between a pair of opposed sidewall surfaces of the gate dielectric, and wherein the gate dielectric is arranged upon a portion of a semiconductor substrate; forming a masking layer across a portion of the gate conductor, wherein the masking layer is arranged upon the portion of the gate conductor a spaced distance from the pair of opposed sidewall surfaces; and removing the gate conductor from the gate dielectric exclusive of the portion of the gate conductor and adjacent to the portion of the gate conductor, thereby exposing a selected region of the gate dielectric on either side of the portion of the gate conductor.
Claim 12
Independent Claim
135 words
A method for forming a transistor, said method comprising: forming a gate conductor upon a gate dielectric having a dielectric constant greater than approximately 3.8, wherein the gate conductor is interposed between a pair of opposed sidewall surfaces of the gate dielectric, and wherein the gate dielectric is arranged upon a portion of a semiconductor substrate; forming a masking layer across a portion of the gate conductor, wherein the masking layer is arranged upon the portion of the gate conductor a spaced distance from the pair of opposed sidewall surfaces; and removing the gate conductor from the gate dielectric exclusive of the portion of the gate conductor and adjacent to the portion of the gate conductor, thereby exposing a selected region of the gate dielectric on either side of the portion of the gate conductor.
Claim 13
Dependent Claim
39 words
The method of claim 10, wherein said forming a masking layer comprises: lithographically patterning a photoresist upon the gate conductor; and isotropically etching the photoresist such that the photoresist is arranged exclusively upon the portion of the gate conductor.
Claim 14
Dependent Claim
18 words
The method of claim 10, further comprising removing the masking layer subsequent to said removing the gate conductor.
Claim 15
Dependent Claim
50 words
The method of claim 12, further comprising forwarding a single impurity distribution into the substrate exclusive of underneath the gate conductor to concurrently form a lightly doped drain area underneath each selected region of the gate dielectric and a pair of source/drain regions laterally adjacent the lightly doped drain areas.
Claim 16
Dependent Claim
25 words
The method of claim 13, wherein a first concentration of the lightly doped drain areas is less than a second concentration of the source/drain regions.
Claim 17
Dependent Claim
18 words
The method of claim 14, wherein the lightly doped drain areas are substantially shallower than the source/drain regions.
Claim 18
Dependent Claim
42 words
The method of claim 14, wherein the semiconductor substrate comprises single crystalline silicon, and further comprising implanting atoms into exposed upper regions of the substrate to form amorphous layers within the exposed upper regions prior to said implanting a single impurity distribution.
Claim 19
Dependent Claim
18 words
The method of claim 16, wherein the atoms are selected from a group consisting of silicon and germanium.
Claim 20
Independent Claim
106 words
A method for forming a transistor upon and within a semiconductor substrate, comprising: forming a gate dielectric upon the semiconductor substrate; forming a gate structure upon the gate dielectric; removing a portion of the gate structure and underlying gate dielectric such that lateral extends of the remaining gate structure align directly over opposed sidewall surfaces of the gate dielectric; removing an additional portion of the remaining gate structure from the gate dielectric a spaced distance from at least one of the opposed sidewall surfaces, thereby forming a gate conductor; and implanting dopants into the substrate partially through regions of the gate dielectric absent the gate conductor.
Claim 21
Independent Claim
106 words
A method for forming a transistor upon and within a semiconductor substrate, comprising: forming a gate dielectric upon the semiconductor substrate; forming a gate structure upon the gate dielectric; removing a portion of the gate structure and underlying gate dielectric such that lateral extends of the remaining gate structure align directly over opposed sidewall surfaces of the gate dielectric; removing an additional portion of the remaining gate structure from the gate dielectric a spaced distance from at least one of the opposed sidewall surfaces, thereby forming a gate conductor; and implanting dopants into the substrate partially through regions of the gate dielectric absent the gate conductor.
Claim 22
Dependent Claim
33 words
The method of claim 18, wherein said removing an additional portion of the remaining gate structures comprises etching the gate structure a substantially equal lateral distance from both of the opposed sidewall surfaces.
Claim 23
Dependent Claim
32 words
The method of claim 18, wherein said removing an additional portion of the remaining gate structures comprises etching the gate structure a lateral distance from only one of the opposed sidewall surfaces.
Claim 24
Dependent Claim
55 words
The method of claim 18, wherein said implanting comprises forwarding dopants into a drain region of the substrate laterally aligned with the gate dielectric concurrent with forwarding dopants into a lightly doped drain region between the drain region and a portion of the substrate aligned beneath the gate conductor after said removing the gate structure.
Claim 25
Dependent Claim
67 words
The method of claim 18, wherein said implanting comprises forwarding dopants into a drain region and a source region of the substrate laterally aligned with respective sidewall surfaces of the gate dielectric concurrent with forwarding dopants into a lightly doped drain region extending between a portion of the substrate aligned beneath the gate conductor and both the source and drain regions after said removing the gate 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) | 2003-11-28 | 2004-05-29 | 2004-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-11-28 | 2008-05-29 | 2008-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-11-28 | 2012-05-29 | 2012-11-28 | $7700.00 | Window Closed / Lapsed |