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US6015746A
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US
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Method of fabricating semiconductor device with a gate-side air-gap structure
Assignee: United Microelectronics Corp
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Filing: 1998-04-07
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Granted: 2000-01-18
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Expires: 2018-04-07
Abstract
Abstract A method of fabricating a semiconductor device. On a semiconductor substrate comprising a device isolation structure and an active region isolated by the device isolation region, an oxide layer is formed and etched on the active region to form an opening, so that the active within the opening is exposed. A first spacer is formed on a side wall of the opening. A gate oxide layer is formed on the active region within the opening. A conductive layer is formed on the gate oxide layer, so that the opening is filled thereby. The oxide layer is removed. The exposed active region is lightly doped to form a lightly doped region by using the conductive layer and the first spacer as a mask. A second spacer is formed on a side wall of the first spacer and leaves a portion of the first spacer to be exposed. The exposed active region is heavily doped to form a source/drain region by using the conductive layer, the first spacer, and the second spacer as a mask. The first spacer is removed to define a gate, so that an air gap between the gate and the second spacer is formed.
Inventors
- 👤 Wen-Kuan Yeh
- 👤 Tony Lin
- 👤 Heng-Sheng Huang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:31
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D30/0225; H10D64/00; H10D64/60; H10D64/66; H10D64/671; H10D64/675; H10D64/679; H10D30/0212; H10D64/20; H10D64/27; H10D64/311; H10D64/411; H10D64/511; H10D64/517; H10D64/518; H10D64/519
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
140 words
A method of fabricating a semiconductor device with a gate-side air-structure (GAS), comprising: providing a substrate having an oxide layer formed thereon; forming an opening within the oxide layer to expose the substrate; forming a first spacer on a side wall of the opening; forming a gate oxide layer on the substrate exposed to the opening; forming a conductive layer on the gate oxide layer, so that the opening is filled thereby; removing the oxide layer; forming a second spacer on a side wall of the first spacer, the second spacer having a height that is less than a height of the first spacer, thereby leaving a portion of the first spacer to be exposed; and removing the first spacer to define the conductive layer, so that an air gap between the conductive layer and the second spacer is formed.
Claim 2
Independent Claim
140 words
A method of fabricating a semiconductor device with a gate-side air-structure (GAS), comprising: providing a substrate having an oxide layer formed thereon; forming an opening within the oxide layer to expose the substrate; forming a first spacer on a side wall of the opening; forming a gate oxide layer on the substrate exposed to the opening; forming a conductive layer on the gate oxide layer, so that the opening is filled thereby; removing the oxide layer; forming a second spacer on a side wall of the first spacer, the second spacer having a height that is less than a height of the first spacer, thereby leaving a portion of the first spacer to be exposed; and removing the first spacer to define the conductive layer, so that an air gap between the conductive layer and the second spacer is formed.
Claim 3
Dependent Claim
20 words
The method according to claim 1, wherein the oxide layer has a thickness of about 1000 Å to 2000 Å.
Claim 4
Dependent Claim
50 words
The method according to claim 1, wherein the first spacer is formed comprising: forming a conformal dielectric layer on the oxide layer and the opening; and performing anisotropic etching to remove a part of the conformal dielectric layer to form the first spacer on a side wall of the opening.
Claim 5
Dependent Claim
16 words
The method according to claim 3 wherein the conformal dielectric layer includes a silicon nitride layer.
Claim 6
Dependent Claim
26 words
The method according to claim 1, wherein the gate oxide layer includes a silicon oxide layer having a thickness of about 100 Å to 250 Å.
Claim 7
Dependent Claim
14 words
The method according to claim 1, wherein the conductive layer includes a poly-silicon layer.
Claim 8
Dependent Claim
52 words
The method according to claim 6, wherein the poly-silicon layer is formed comprising: forming a poly-silicon layer on the oxide layer, the first spacer and the gate oxide layer to fill the opening, doping the poly-silicon layer; and performing a planarization process to the poly-silicon layer until the oxide layer is exposed.
Claim 9
Dependent Claim
20 words
The method according to claim 7, wherein the poly-silicon layer has a thickness of about 2000 Å to 3000 Å.
Claim 10
Dependent Claim
15 words
The method according to claim 7, wherein the poly-silicon layer is planarized by chemical-mechanical polish.
Claim 11
Dependent Claim
15 words
The method according to claim 1, wherein the oxide layer is removed by wet etching.
Claim 12
Dependent Claim
36 words
The method according to claim 1, wherein after the removing the oxide layer and before forming the second spacer, the substrate is lightly doped by using the conductive layer and the first spacer as a mask.
Claim 13
Dependent Claim
34 words
The method according to claim 1, wherein after the formation of the second spacer, the substrate is heavily doped by using the conductive layer, the first spacer, and the second spacer as a mask.
Claim 14
Dependent Claim
13 words
The method according to claim 1, wherein the conductive line includes a poly-line.
Claim 15
Independent Claim
205 words
A method of fabricating a semiconductor device with a gate-side air-gap structure (GAS), comprising: providing a substrate with an isolation structure and an active region isolated by the isolation structure; forming an oxide layer on the substrate; forming an opening within the oxide layer to expose the active region; forming a first spacer on a side wall of the opening; forming a gate oxide layer on the active region exposed to the opening; forming a conductive layer on the gate oxide layer, so that the opening is filled thereby; removing the oxide layer; lightly doping the exposed active region to form a lightly doped region by using the conductive layer and the first spacer as a mask; forming a second spacer on a side wall of the first spacer, the second spacer having a height that is less than a height of the first spacer, thereby leaving a portion of the first spacer to be exposed; heavily doping the exposed active region to form a source/drain region by using the conductive layer, the first spacer, and the second spacer as a mask; and removing the first spacer to define a gate, so that an air gap between the gate and the second spacer is formed.
Claim 16
Independent Claim
205 words
A method of fabricating a semiconductor device with a gate-side air-gap structure (GAS), comprising: providing a substrate with an isolation structure and an active region isolated by the isolation structure; forming an oxide layer on the substrate; forming an opening within the oxide layer to expose the active region; forming a first spacer on a side wall of the opening; forming a gate oxide layer on the active region exposed to the opening; forming a conductive layer on the gate oxide layer, so that the opening is filled thereby; removing the oxide layer; lightly doping the exposed active region to form a lightly doped region by using the conductive layer and the first spacer as a mask; forming a second spacer on a side wall of the first spacer, the second spacer having a height that is less than a height of the first spacer, thereby leaving a portion of the first spacer to be exposed; heavily doping the exposed active region to form a source/drain region by using the conductive layer, the first spacer, and the second spacer as a mask; and removing the first spacer to define a gate, so that an air gap between the gate and the second spacer is formed.
Claim 17
Dependent Claim
20 words
The method according to claim 14, wherein the oxide layer has a thickness of about 1000 Å to 2000 Å.
Claim 18
Dependent Claim
50 words
The method according to claim 14, wherein the first spacer is formed comprising: forming a conformal dielectric layer on the oxide layer and the opening; and performing anisotropic etching to remove a part of the conformal dielectric layer to form the first spacer on a side wall of the opening.
Claim 19
Dependent Claim
16 words
The method according to claim 16, wherein the conformal dielectric layer include a silicon nitride layer.
Claim 20
Dependent Claim
26 words
The method according to claim 14, wherein the gate oxide layer includes a silicon oxide layer having a thickness of about 100 Å to 250 Å.
Claim 21
Dependent Claim
14 words
The method according to claim 14, wherein the conductive layer includes a poly-silicon layer.
Claim 22
Dependent Claim
52 words
The method according to claim 14, wherein the poly-silicon layer is formed comprising: forming a poly-silicon layer on the oxide layer, the first spacer and the gate oxide layer to fill the opening; doping the poly-silicon layer; and performing a planarization process to the poly-silicon layer until the oxide layer is exposed.
Claim 23
Dependent Claim
20 words
The method according to claim 20, wherein the poly-silicon layer has a thickness of about 2000 Å to 3000 Å.
Claim 24
Dependent Claim
15 words
The method according to claim 20, wherein the poly-silicon layer is planarized by chemical-mechanical polish.
Claim 25
Dependent Claim
15 words
The method according to claim 14, wherein the oxide layer is removed by wet etching.
Claim 26
Dependent Claim
13 words
The method according to claim 14, wherein the conductive line includes a poly-line.
References Cited (Backward Citations)
US5668021A
Cited
US5786256A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-01-17 | 2003-07-19 | 2004-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-01-17 | 2007-07-19 | 2008-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-01-17 | 2011-07-19 | 2012-01-18 | $7700.00 | Window Closed / Lapsed |