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US5770508A
Expired / Lapsed
US
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Method of forming lightly doped drains in metalic oxide semiconductor components
Assignee: United Microelectronics Corp
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Filing: 1997-06-04
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Granted: 1998-06-23
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Expires: 2017-06-04
Abstract
Abstract The present invention relates to a method of forming lightly doped drains in metallic oxide semiconductor (MOS) components. The method includes forming a first, second, and third insulating layer above a silicon substrate having a gate, etching back the layers to leave behind L-shaped first spacers on sidewalls of the gate, followed by doping second type ions into the silicon substrate to form first lightly doped drains in the silicon substrate surface below the L-shaped first spacers, and second lightly doped drains in the silicon substrate surface elsewhere, further forming a fourth insulating to form third spacers, and using the using the third spacers, the first insulating layer, and the gate as masks when doping second type ions into the silicon substrate so as to form source/drain regions in silicon substrate surfaces not covered by the third spacers. Such a method produces greater yield and reduces leakage current from the transistor components.
Inventors
- 👤 Wen-Kuan Yeh
- 👤 Coming Chen
- 👤 Jih-Wen Chou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:10
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D30/0227; H10D30/0229; H10D30/60; H10D30/601; H10D64/00; H10D64/01; H10D64/021
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
179 words
A method of forming lightly doped drains in MOS components comprising: providing a silicon substrate doped with first type ions, a first insulating layer, and a gate; forming a second insulating layer and a third insulating layer above the silicon substrate; etching back the third and the second insulating layers so as to completely remove the second insulating layer above the gate while leaving behind L-shaped first spacers and second spacers on sidewalls of the gate; removing the second spacers, followed by doping second type ions into the silicon substrate to form first lightly doped drains in the silicon substrate surface below the L-shaped first spacers, and second lightly doped drains in the silicon substrate surface elsewhere; forming a fourth insulating layer above the silicon substrate, followed by etching back the fourth insulating layer so as to form third spacers; and using the third spacers, the first insulating layer, and the gate as masks when doping second type ions into the silicon substrate so as to form source/drain regions in silicon substrate surfaces not covered by the third spacers.
Claim 2
Independent Claim
179 words
A method of forming lightly doped drains in MOS components comprising: providing a silicon substrate doped with first type ions, a first insulating layer, and a gate; forming a second insulating layer and a third insulating layer above the silicon substrate; etching back the third and the second insulating layers so as to completely remove the second insulating layer above the gate while leaving behind L-shaped first spacers and second spacers on sidewalls of the gate; removing the second spacers, followed by doping second type ions into the silicon substrate to form first lightly doped drains in the silicon substrate surface below the L-shaped first spacers, and second lightly doped drains in the silicon substrate surface elsewhere; forming a fourth insulating layer above the silicon substrate, followed by etching back the fourth insulating layer so as to form third spacers; and using the third spacers, the first insulating layer, and the gate as masks when doping second type ions into the silicon substrate so as to form source/drain regions in silicon substrate surfaces not covered by the third spacers.
Claim 3
Dependent Claim
16 words
A method of forming according to claim 1, wherein the first type ions are boron ions.
Claim 4
Dependent Claim
18 words
A method of forming according to claim 1, wherein the first insulating layer is a field oxide layer.
Claim 5
Dependent Claim
18 words
A method of forming according to claim 1, wherein the first insulating layer is a shallow trench isolation.
Claim 6
Dependent Claim
18 words
A method of forming according to claim 1, wherein the second insulating layer is a silicon dioxide layer.
Claim 7
Dependent Claim
24 words
A method of forming according to claim 1, wherein the thickness of the second insulating layer is between about 100 Å to 200 Å.
Claim 8
Dependent Claim
18 words
A method of forming according to claim 1, wherein the third insulating layer is a silicon nitride layer.
Claim 9
Dependent Claim
24 words
A method of forming according to claim 1, wherein the thickness of the third insulating layer is between about 1500 Å to 2000 Å.
Claim 10
Dependent Claim
16 words
A method of forming according to claim 1, wherein the second type ions are arsenic ions.
Claim 11
Dependent Claim
24 words
A method of forming according to claim 1, wherein the doping energy for the second type ions is between about 10 to 200 KeV.
Claim 12
Dependent Claim
23 words
A method of forming according to claim 1, wherein the etching back to process is performed using an anisotropic reactive ion etching method.
Claim 13
Dependent Claim
24 words
A method of forming according to claim 1, wherein the second spacers are removed by a wet etching method using hot phosphoric acid solution.
Claim 14
Dependent Claim
20 words
A method of forming according to claim 1, wherein the first lightly doped drain is a shallow source/drain extension region.
Claim 15
Dependent Claim
20 words
A method of forming according to claim 1, wherein the second lightly doped drain is a moderate source/drain extension region.
Claim 16
Dependent Claim
18 words
A method of forming according to claim 1, wherein the fourth insulating layer is a silicon dioxide layer.
Claim 17
Dependent Claim
24 words
A method of forming according to claim 15, wherein the thickness of the silicon dioxide layer is between about 1500 Å to 2500 Å.
Claim 18
Dependent Claim
18 words
A method of forming according to claim 1, wherein the fourth insulating layer is a silicon nitride layer.
Claim 19
Dependent Claim
24 words
A method of forming according to claim 17, wherein the thickness of the silicon nitride layer is between about 2000 Å to 2500 Å.
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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) | 2001-06-22 | 2001-12-22 | 2002-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-22 | 2005-12-22 | 2006-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-22 | 2009-12-22 | 2010-06-23 | $7700.00 | Window Closed / Lapsed |