US5958508A
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US
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Process for forming a semiconductor device
Assignee: NXP USA Inc
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Filing: 1997-03-31
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Granted: 1999-09-28
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Expires: 2017-03-31
Abstract
Abstract A metal-semiconductor layer (26) is formed over an insulating layer (20) such that the metal-semiconductor layer (26) is graded to have varying amounts of the semiconductor and metal throughout the layer. In one embodiment, the metal-semiconductor layer (26) has relatively higher silicon content near the layer's lower and upper surfaces. At the midpoint, the layer is close to stoichiometric tungsten silicide. In another embodiment, a metal-semiconductor-nitrogen layer is formed having nitrogen nearer the lower surface and essentially no nitrogen near the upper surface. The layer (26) can be formed using chemical vapor deposition or sputtering.
Inventors
- 👤 Olubunmi Olufemi Adetutu
- 👤 Dean J. Denning
- 👤 James D. Hayden
- 👤 Chitra K. Subramanian
- 👤 Arkalgud R. Sitaram
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:30
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/44; C23C16/455; C23C16/45523; H; H10; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/0698
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
162 words
A process for forming a semiconductor device comprising the steps of: forming an insulating layer over a semiconductor device substrate; and forming a first layer over the insulating layer, wherein: the first layer includes a semiconductor and a metal; the first layer has a first surface and a second surface that is further from the insulating layer compared to the first surface; the first layer has a first location, a second location, and a third location, wherein the first location is closest to the first surface, the third location is closest to the second surface, and the second location lies between the first and second surfaces; and within the first layer, a semiconductor content is selected from a group consisting of: essentially stoichiometric at the second location and above 80 atomic percent at the first location or the third location; and at most 60 atomic percent at the second location and at least stoichiometric at the first location or the third location.
Claim 2
Dependent Claim
162 words
A process for forming a semiconductor device comprising the steps of: forming an insulating layer over a semiconductor device substrate; and forming a first layer over the insulating layer, wherein: the first layer includes a semiconductor and a metal; the first layer has a first surface and a second surface that is further from the insulating layer compared to the first surface; the first layer has a first location, a second location, and a third location, wherein the first location is closest to the first surface, the third location is closest to the second surface, and the second location lies between the first and second surfaces; and within the first layer, a semiconductor content is selected from a group consisting of: essentially stoichiometric at the second location and above 80 atomic percent at the first location or the third location; and at most 60 atomic percent at the second location and at least stoichiometric at the first location or the third location.
Claim 3
Dependent Claim
19 words
The process of claim 1, wherein the semiconductor content at the first location is at least 80 atomic percent.
Claim 4
Dependent Claim
72 words
The process of claim 2, wherein: the first location lies within a first portion of the first layer and the second location lies within a second portion of the first layer; a metal content within the second portion is essentially stoichiometric and the metal content within the first portion is at most 20 atomic percent; and the second portion is in a range of approximately 2-10 times thicker than the first portion.
Claim 5
Dependent Claim
19 words
The process of claim 1, wherein the semiconductor content at the third location is at least 80 atomic percent.
Claim 6
Dependent Claim
84 words
The process of claim 4, wherein: the first location lies within a first portion of the first layer, the second location lies within a second portion of the first layer, and the third location lies within a third portion of the first layer; a metal content within the second portion is essentially stoichiometric and the metal content within the third portion is at most 20 atomic percent; and the second portion is in a range of approximately 2-10 times thicker than the first portion.
Claim 7
Dependent Claim
25 words
The process of claim 1, wherein the semiconductor content at each of the first location and the third location is at least 80 atomic percent.
Claim 8
Dependent Claim
23 words
The process of claim 1, wherein the first layer has a portion that has a metal content of at least 40 atomic percent.
Claim 9
Dependent Claim
19 words
The process of claim 1, wherein the step of forming the, first layer is performed using chemical vapor deposition.
Claim 10
Dependent Claim
33 words
The process of claim 8, wherein the step of forming the first layer is performed at a temperature in a range of approximately 350-475 degrees Celsius and a pressure less than one torr.
Claim 11
Dependent Claim
18 words
The process of claim 1, further comprising a step of forming a passivation layer over the first layer.
Claim 12
Dependent Claim
34 words
The process of claim 1, wherein: the step of forming the first layer is performed by sputtering; and the process further comprises annealing the first layer after the step of forming the first layer.
Claim 13
Dependent Claim
35 words
The process of claim 1, wherein: the insulating layer is a gate dielectric layer; the semiconductor device includes a memory array; and the process further comprising patterning the first layer to form a gate electrode.
Claim 14
Dependent Claim
80 words
A process for forming a semiconductor device comprising the steps of: forming an insulating layer over a semiconductor device substrate; and forming a first layer over the insulating layer using a nitrogen-containing gas, wherein: the first layer includes a semiconductor, a metal, and nitrogen and has a metal content, a semiconductor content, and a nitrogen content; and the nitrogen-containing gas flows during at least a portion of the step but is terminated before completing the formation of the first layer.
Claim 15
Dependent Claim
80 words
A process for forming a semiconductor device comprising the steps of: forming an insulating layer over a semiconductor device substrate; and forming a first layer over the insulating layer using a nitrogen-containing gas, wherein: the first layer includes a semiconductor, a metal, and nitrogen and has a metal content, a semiconductor content, and a nitrogen content; and the nitrogen-containing gas flows during at least a portion of the step but is terminated before completing the formation of the first layer.
Claim 16
Dependent Claim
16 words
The process of claim 13, wherein the nitrogen content is substantially zero at the second location.
Claim 17
Dependent Claim
19 words
The process of claim 13, wherein the step of forming the first layer is performed using chemical vapor deposition.
Claim 18
Dependent Claim
35 words
The process of claim 13, wherein: the insulating layer is a gate dielectric layer; the semiconductor device includes a memory array; and the process further comprising patterning the first layer to form a gate electrode.
Claim 19
Dependent Claim
18 words
The process of claim 13, further comprising at step of forming a passivation layer over the first layer.
Claim 20
Dependent Claim
32 words
The process of claim 13, wherein during the step of forming the layer, a second gas flows after the nitrogen-containing gas is terminated and before completing the formation of the first layer.
Claim 21
Dependent Claim
11 words
The process of claim 18, wherein the second gas includes argon.
Claim 22
Dependent Claim
13 words
The process of claim 18, wherein the second gas includes an ionized gas.
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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) | 2002-09-27 | 2003-03-29 | 2003-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-09-27 | 2007-03-29 | 2007-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-09-27 | 2011-03-29 | 2011-09-28 | $7700.00 | Window Closed / Lapsed |