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US5811342A
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Method for forming a semiconductor device with a graded lightly-doped drain structure
Assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
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Filing: 1998-01-26
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Granted: 1998-09-22
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Expires: 2018-01-26
Abstract
Abstract A method for forming a semiconductor device with a graded lightly-doped drain (LDD) structure is disclosed. The method includes providing a semiconductor substrate (10) having a gate region (14 and 16) thereon, followed by forming a pad layer (18) on the substrate and the gate region. Next, ions are implanted into the substrate, and a spacer (22) is formed on sidewalls of the gate region, wherein the first spacer has a concave surface inwards on a surface of the first spacer. Finally, ions are further implanted into the substrate using the gate region and the spacer as a mask, thereby forming a graded doping profile (20) in the substrate.
Inventors
- 👤 Shye-Lin Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 08:06
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D30/0227; H10D30/60; H10D30/601; H10D64/00; H10D64/01; H10D64/015; H10P; H10P30/00; H10P30/20; H10P30/22; Y; Y10; Y10S; Y10S148/00; Y10S148/106; Y10S148/161; Y10S257/00; Y10S257/90; Y10S438/00; Y10S438/965
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
88 words
A method for forming a graded lightly-doped drain structure in a semiconductor device, said method comprising: providing a semiconductor substrate having a gate region thereon; forming a pad layer on said substrate and said gate region; implanting ions into said substrate; forming a spacer on sidewalls of said gate region, said spacer having a concave surface inwards on a surface of said spacer; and implanting ions into said substrate using the gate region and the spacer as a mask, thereby forming a graded doping profile in said substrate.
Claim 2
Independent Claim
88 words
A method for forming a graded lightly-doped drain structure in a semiconductor device, said method comprising: providing a semiconductor substrate having a gate region thereon; forming a pad layer on said substrate and said gate region; implanting ions into said substrate; forming a spacer on sidewalls of said gate region, said spacer having a concave surface inwards on a surface of said spacer; and implanting ions into said substrate using the gate region and the spacer as a mask, thereby forming a graded doping profile in said substrate.
Claim 3
Dependent Claim
28 words
The method according to claim 1, wherein said gate region comprises a polysilicon region formed on said substrate, and a silicon oxide region formed on said polysilicon region.
Claim 4
Dependent Claim
37 words
The method according to claim 1, wherein said spacer is formed by the steps of: coating a spin-on-glass film over said pad layer; reflowing said spin-on-glass film; and etching back said spin-on-glass film, thereby forming said spacer.
Claim 5
Dependent Claim
13 words
The method according to claim 1, wherein said pad layer comprises silicon nitride.
Claim 6
Independent Claim
111 words
A method for forming a semiconductor device with a graded lightly-doped drain structure, said method comprising: providing a semiconductor substrate having a gate region thereon; forming a pad layer on said substrate and said gate region; implanting ions into said substrate; forming a first spacer on sidewalls of said gate region, said first spacer having a concave surface inwards on a surface of said first spacer; implanting ions into said substrate using the gate region and the first spacer as a mask, thereby forming a graded doping profile in said substrate; removing said first spacer and said pad layer; and forming a second spacer on the sidewalls of said gate region.
Claim 7
Independent Claim
111 words
A method for forming a semiconductor device with a graded lightly-doped drain structure, said method comprising: providing a semiconductor substrate having a gate region thereon; forming a pad layer on said substrate and said gate region; implanting ions into said substrate; forming a first spacer on sidewalls of said gate region, said first spacer having a concave surface inwards on a surface of said first spacer; implanting ions into said substrate using the gate region and the first spacer as a mask, thereby forming a graded doping profile in said substrate; removing said first spacer and said pad layer; and forming a second spacer on the sidewalls of said gate region.
Claim 8
Dependent Claim
20 words
The method according to claim 5, further comprising annealing said substrate, thereby smoothing said graded doping profile in said substrate.
Claim 9
Dependent Claim
28 words
The method according to claim 5, wherein said gate region comprises a polysilicon region formed on said substrate, and a silicon oxide region formed on said polysilicon region.
Claim 10
Dependent Claim
13 words
The method according to claim 5, wherein said pad layer comprises silicon nitride.
Claim 11
Dependent Claim
39 words
The method according to claim 5, wherein said first spacer is formed by the steps of: coating a spin-on-glass film over said pad layer; reflowing said spin-on-glass film; and etching back said spin-on-glass film, thereby forming said first spacer.
Claim 12
Dependent Claim
38 words
The method according to claim 5, wherein said second spacer is formed by the steps of: depositing a dielectric layer over said gate region and said substrate; and etching back said dielectric layer, thereby forming said second spacer.
Claim 13
Dependent Claim
13 words
The method according to claim 5, wherein said second spacer comprises silicon oxide.
Claim 14
Dependent Claim
13 words
The method according to claim 5, wherein said second spacer comprises silicon nitride.
Claim 15
Independent Claim
166 words
A method for forming a semiconductor device with a graded lightly-doped drain structure, said method comprising: providing a semiconductor substrate having a gate region thereon; forming a silicon nitride layer on said substrate and said gate region; implanting ions into said substrate; coating a spin-on-glass film over said silicon nitride layer; reflowing said spin-on-glass film; etching back said spin-on-glass film to forming a first spacer on sidewalls of said gate region, said first spacer having a concave surface inwards on a surface of said first spacer; implanting ions into said substrate through said silicon nitride layer using the gate region and the first spacer as a mask, thereby forming a graded doping profile in said substrate; removing said first spacer and said silicon nitride layer; depositing a dielectric layer over said gate region and said substrate; etching back said dielectric layer, thereby forming a second spacer on the sidewalls of said gate region; and annealing said substrate, thereby smoothing said graded doping profile in said substrate.
Claim 16
Independent Claim
166 words
A method for forming a semiconductor device with a graded lightly-doped drain structure, said method comprising: providing a semiconductor substrate having a gate region thereon; forming a silicon nitride layer on said substrate and said gate region; implanting ions into said substrate; coating a spin-on-glass film over said silicon nitride layer; reflowing said spin-on-glass film; etching back said spin-on-glass film to forming a first spacer on sidewalls of said gate region, said first spacer having a concave surface inwards on a surface of said first spacer; implanting ions into said substrate through said silicon nitride layer using the gate region and the first spacer as a mask, thereby forming a graded doping profile in said substrate; removing said first spacer and said silicon nitride layer; depositing a dielectric layer over said gate region and said substrate; etching back said dielectric layer, thereby forming a second spacer on the sidewalls of said gate region; and annealing said substrate, thereby smoothing said graded doping profile in said substrate.
Claim 17
Dependent Claim
28 words
The method according to claim 13, wherein said gate region comprises a polysilicon region formed on said substrate, and a silicon oxide region formed on said polysilicon region.
Claim 18
Dependent Claim
13 words
The method according to claim 13, wherein said dielectric layer comprises silicon nitride.
Claim 19
Dependent Claim
13 words
The method according to claim 13, wherein said dielectric layer comprises silicon oxide.
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