US5994183A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming charge storage structure
Assignee: United Microelectronics Corp
•
Filing: 1997-12-23
•
Granted: 1999-11-30
•
Expires: 2017-12-23
Abstract
Abstract A method for forming a high capacitance charge storage structure that can be applied to a substrate wafer having MOS transistor already formed thereon. The method is to form an insulating layer above the substrate wafer. Next, a contact window exposing a source/drain region is formed in the insulating layer. Then, a tungsten suicide layer, which functions as a lower electrode for the charge storage structure, is formed over the substrate. Thereafter, a tungsten nitride layer is formed over the tungsten silicide layer, and then a dielectric layer is formed over the tungsten nitride layer. The dielectric layer is preferably a tantalum oxide layer. Finally, a titanium nitride layer, which functions as an upper electrode for the charge storage structure, is formed over the tantalum oxide layer.
Inventors
- 👤 Kuo-Tai Huang
- 👤 Wen-Yi Hsieh
- 👤 Tri-Rung Yew
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:12
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/692; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
142 words
A method for forming a charge storage structure that can be applied to a substrate wafer having a MOS transistor already formed thereon, wherein an insulating layer has been formed over the substrate wafer, and furthermore, a contact window has been formed in the insulating layer exposing a source/drain region, comprising the steps of: forming a metal silicide layer in the contact window and over the surface of the insulating layer, wherein the metal silicide layer functions as the lower electrode of the charge storage structure; forming a first metal nitride layer over the metal silicide layer to protect the metal silicide layer from oxidation; forming a dielectric layer over the first metal silicide layer; and forming a second metal nitride layer over the dielectric layer, wherein the second metal nitride layer functions as the upper electrode of the charge storage structure.
Claim 2
Independent Claim
142 words
A method for forming a charge storage structure that can be applied to a substrate wafer having a MOS transistor already formed thereon, wherein an insulating layer has been formed over the substrate wafer, and furthermore, a contact window has been formed in the insulating layer exposing a source/drain region, comprising the steps of: forming a metal silicide layer in the contact window and over the surface of the insulating layer, wherein the metal silicide layer functions as the lower electrode of the charge storage structure; forming a first metal nitride layer over the metal silicide layer to protect the metal silicide layer from oxidation; forming a dielectric layer over the first metal silicide layer; and forming a second metal nitride layer over the dielectric layer, wherein the second metal nitride layer functions as the upper electrode of the charge storage structure.
Claim 3
Dependent Claim
12 words
The method of claim 1, wherein the insulating layer is an oxide.
Claim 4
Dependent Claim
29 words
The method of claim 1, wherein the step of forming the metal silicide layer includes depositing a tungsten silicide WSi x such that the x is smaller than 2.2.
Claim 5
Dependent Claim
18 words
The method of claim 1, wherein the metal silicide layer has a thickness of about 1000Å to 2000Å.
Claim 6
Dependent Claim
19 words
The method of claim 1, wherein the step of forming the first metal nitride layer includes depositing tungsten nitride.
Claim 7
Dependent Claim
21 words
The method of claim 5, wherein the step of forming the tungsten nitride layer includes using a rapid thermal processing method.
Claim 8
Dependent Claim
30 words
The method of claim 6, wherein the rapid thermal processing operates in an atmosphere of nitrogen at a temperature of about 800° C. to 1000° C. for about 15-60 seconds.
Claim 9
Dependent Claim
17 words
The method of claim 1, wherein the step of forming the dielectric layer includes depositing tantalum oxide.
Claim 10
Dependent Claim
22 words
The method of claim 8, wherein the step of forming the dielectric layer includes using a low pressure chemical vapor deposition method.
Claim 11
Dependent Claim
15 words
The method of claim 8, wherein the thickness of the dielectric layer is about 50Å-140Å.
Claim 12
Dependent Claim
19 words
The method of claim 1, wherein the step of forming the second metal nitride layer includes depositing titanium nitride.
Claim 13
Dependent Claim
18 words
The method of claim 3, wherein the tungsten silicide WSi x is deposited by a sputtering deposition method.
Claim 14
Dependent Claim
23 words
The method of claim 12, wherein after the tungsten silicide WSi x is deposited, the deposited tungsten silicide WSi x layer is annealed.
Claim 15
Dependent Claim
23 words
The method of claim 1, wherein the metal silicide layer is formed in direct contact with the source/drain region in the contact window.
References Cited (Backward Citations)
US4984030A
Cited
US4918502A
Cited
US5187566A
Cited
US5025741A
Cited
US5234859A
Cited
US5049975A
Cited
US5309023A
Cited
US5192713A
Cited
US5712194A
Cited
US5393565A
Cited
US5471418A
Cited
US5413950A
Cited
US5380673A
Cited
US5480837A
Cited
US5539231A
Cited
US5838051A
Cited
US5747845A
Cited
US5759889A
Cited
US5789290A
Cited
US5837579A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-11-29 | 2003-05-31 | 2003-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-11-29 | 2007-05-31 | 2007-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-11-29 | 2011-05-31 | 2011-11-30 | $7700.00 | Window Closed / Lapsed |