US5893740A
Expired / Lapsed
US
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Method of forming a short channel field effect transistor
Assignee: National Science and Technology Council
•
Filing: 1997-01-27
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Granted: 1999-04-13
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Expires: 2017-01-27
Abstract
Abstract A method of forming a short channel field effect transistor is disclosed. The method includes the steps of providing a semiconductor substrate having a well region of a first conductivity type; forming a gate electrode on the well region; implanting first impurities into the well region and adjacent to the gate electrode, the first implant step being at a first dose and a second conductivity type; forming sidewall spacers on edges of the gate electrode; implanting second impurities into the well region and adjacent to the gate electrode, the second implant step being at a second dose and at the second conductivity type; and implanting third impurities into the well region and adjacent the gate electrode, the third implant step being at a third dose and at the first conductivity type.
Inventors
- 👤 Chun-Yeh Chang
- 👤 I-Feng Tseng
- 👤 Jaw-Jia Tsai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:36
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0217; H10D30/0212; H10D30/0223; H10D30/0227; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/221; H10D62/235; H10D62/314; H10D62/351; H10D62/357; H10D62/364; H10D62/371; H10P; H10P30/00; H10P30/20; H10P30/22; H10P30/221; H10P30/222
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
150 words
A method of forming a semiconductor integrated circuit comprising the steps of: providing a semiconductor substrate having a well region of a first conductivity type; forming a gate electrode on said well region; implanting first impurities into said well region and adjacent to said gate electrode, said first implant step being at a first dose and a second conductivity type; forming sidewall spacers on edges of said gate electrode; implanting second impurities into said well region and adjacent to said gate electrode, said second implant step being at a second dose and at said second conductivity type; and implanting third impurities by a tilt implant into said well region and adjacent said gate electrode, said third implant step being at a third dose and at said first conductivity type, wherein a channel region underlies said gate electrode, and said third implant step forms an ion-implanted region under said channel region.
Claim 2
Independent Claim
150 words
A method of forming a semiconductor integrated circuit comprising the steps of: providing a semiconductor substrate having a well region of a first conductivity type; forming a gate electrode on said well region; implanting first impurities into said well region and adjacent to said gate electrode, said first implant step being at a first dose and a second conductivity type; forming sidewall spacers on edges of said gate electrode; implanting second impurities into said well region and adjacent to said gate electrode, said second implant step being at a second dose and at said second conductivity type; and implanting third impurities by a tilt implant into said well region and adjacent said gate electrode, said third implant step being at a third dose and at said first conductivity type, wherein a channel region underlies said gate electrode, and said third implant step forms an ion-implanted region under said channel region.
Claim 3
Dependent Claim
27 words
A method as set forth in claim 1 wherein said second implant step forms source and drain regions of a field effect transistor at said well region.
Claim 4
Dependent Claim
31 words
A method as set forth in claim 2 before said third implant step further comprising a step of forming silicide layers respectively on said gate electrode, said source, and said drain.
Claim 5
Dependent Claim
16 words
A method as set forth in claim 1 wherein first dose is less than second dose.
Claim 6
Dependent Claim
26 words
A method as set forth in claim 1 wherein said first conductivity type is an N type and said second conductivity type is a P type.
Claim 7
Dependent Claim
16 words
A method as set forth in claim 5 wherein said N type impurities are phosphorus ions.
Claim 8
Dependent Claim
16 words
A method as set forth in claim 5 wherein said N type impurities are arsenic ions.
Claim 9
Dependent Claim
16 words
A method as set forth in claim 5 wherein said P type impurities are boron ions.
Claim 10
Dependent Claim
18 words
A method as set forth in claim 5 wherein said P type impurities are BF 2 + .
Claim 11
Dependent Claim
26 words
A method as set forth in claim 1 wherein said first conductivity type is a P type and said second conductivity type is an N type.
Claim 12
Dependent Claim
16 words
A method as set forth in claim 10 wherein said N type impurities are arsenic ions.
Claim 13
Dependent Claim
16 words
A method as set forth in claim 10 wherein said N type impurities are phosphorus ions.
Claim 14
Dependent Claim
16 words
A method as set forth in claim 10 wherein said P type impurities are boron ions.
Claim 15
Dependent Claim
18 words
A method as set forth in claim 10 wherein said P type impurities are BF 2 + .
Claim 16
Dependent Claim
21 words
A method as set forth in claim 1 wherein said gate electrode comprises a polysilicon layer and a gate oxide layer.
Claim 17
Dependent Claim
30 words
A method as set forth in claim 1, wherein angle of said third implant step includes an angle greater than about 30 degrees from a perpendicular from said gate electrode.
Claim 18
Dependent Claim
25 words
A method as set forth in claim 1 wherein said first implant step forms an LDD region of a field effect transistor at said well.
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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) | 2002-04-12 | 2002-10-12 | 2003-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-04-12 | 2006-10-12 | 2007-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-04-12 | 2010-10-12 | 2011-04-13 | $7700.00 | Window Closed / Lapsed |