US4829363A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Structure for inhibiting dopant out-diffusion
Assignee: National Semiconductor Corp
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Filing: 1988-07-25
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Granted: 1989-05-09
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Expires: 2008-07-25
Abstract
Abstract A method for inhibiting out-diffusion of dopants from polycrystalline or single crystal silicon substrates of high speed semiconductor devices into metal silicide conductive layers disposed on the substrate comprises interposing a refractory metal nitride layer between the doped silicon substrate and the refractory metal silicide conductive layer. Dopant out-diffusion is further retarded, and contact resistance lowered, by adding a thin layer of refractory metal between the refractory metal nitride layer and the silicon substrate.
Inventors
- 👤 Michael E. Thomas
- 👤 Madhukar B. Vora
- 👤 Ashok K. Kapoor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:52
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/66; H10D64/661; H10D64/662; H10D64/664; H10D62/00; H10D62/80; H10D62/83; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01306; H10D64/01308; H10D64/01312; H10D64/62; H10W; H10W20/00; H10W20/40; H10W20/41; H10W20/44; H10W20/4403; H10W20/4437; H10W20/4441; Y; Y10; Y10S; Y10S257/00; Y10S257/915
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
93 words
In a semiconductor device comprising a silicon substrate containing a dopant and having a refractory metal silicide layer disposed on at least a portion of one surface thereof, means for preventing out-diffusion of said dopant from said silicon substate into said refractory metal silicide layer, said means comprising a refractory metal nitride barrier layer disposed between said substrate and said refractory metal silicide layer whereby said refractory metal nitride barrier layer is in contact with said substrate and said refractory metal silicide layer is in contact with said refractory metal nitride barrier layer.
Claim 2
Dependent Claim
93 words
In a semiconductor device comprising a silicon substrate containing a dopant and having a refractory metal silicide layer disposed on at least a portion of one surface thereof, means for preventing out-diffusion of said dopant from said silicon substate into said refractory metal silicide layer, said means comprising a refractory metal nitride barrier layer disposed between said substrate and said refractory metal silicide layer whereby said refractory metal nitride barrier layer is in contact with said substrate and said refractory metal silicide layer is in contact with said refractory metal nitride barrier layer.
Claim 3
Dependent Claim
30 words
The device in accordance with claim 1 wherein said refractory metal nitride layer comprises a refractory metal selected from the group consisting of tantalum, niobium, titanium, zirconium, chromium and hafnium.
Claim 4
Dependent Claim
22 words
The device in accordance with claim 2 wherein said dopant is selected from the group consisting of boron, phosporous, arsenic and antimony.
Claim 5
Dependent Claim
88 words
In a semiconductor device comprising a silicon substrate containing a dopant and having a refractory metal layer disposed on at least one portion of one surface thereof, means for blocking transport of said dopant from said substrate into said refractory metal layer, said means comprising a refractory metal nitride barrier layer disposed between said substrate and said refractory metal layer whereby said refractory metal nitride barrier layer is in contact with said substrate and said refractory metal layer is in contact with said refractory metal nitride barrier layer.
Claim 6
Dependent Claim
88 words
In a semiconductor device comprising a silicon substrate containing a dopant and having a refractory metal layer disposed on at least one portion of one surface thereof, means for blocking transport of said dopant from said substrate into said refractory metal layer, said means comprising a refractory metal nitride barrier layer disposed between said substrate and said refractory metal layer whereby said refractory metal nitride barrier layer is in contact with said substrate and said refractory metal layer is in contact with said refractory metal nitride barrier layer.
Claim 7
Dependent Claim
28 words
The device in accordance with claim 4 wherein said barrier layer includes a refractory metal selected from the group consisting of tantalum, niobium, titanium, zirconium, chromium and hafnium.
Claim 8
Dependent Claim
27 words
The device in accordance with claim 5 wherein said first refractory metal layer comprises a refractory metal selected from the group consisting of molybdenum, tungsten and tantalum.
Claim 9
Dependent Claim
110 words
In a semiconductor device comprising a silicon substrate containing a dopant and having a refractory metal silicide layer disposed on at least a portion of one surface thereof: (a) means for preventing out-diffusion of said dopant from said silicon substrate into said refractory metal silicide layer, said out-diffusion preventing means comprising a refractory metal nitride barrier layer disposed between said substrate and said refractory metal silicide layer; and (b) means for reducing contact resistance, said contact resistance reducing means comprising a thin layer of refractory metal disposed between said barrier layer and said silicon substrate, said thin layer of refractory metal having a thickness which does not exceed approximately 100Å.
Claim 10
Dependent Claim
110 words
In a semiconductor device comprising a silicon substrate containing a dopant and having a refractory metal silicide layer disposed on at least a portion of one surface thereof: (a) means for preventing out-diffusion of said dopant from said silicon substrate into said refractory metal silicide layer, said out-diffusion preventing means comprising a refractory metal nitride barrier layer disposed between said substrate and said refractory metal silicide layer; and (b) means for reducing contact resistance, said contact resistance reducing means comprising a thin layer of refractory metal disposed between said barrier layer and said silicon substrate, said thin layer of refractory metal having a thickness which does not exceed approximately 100Å.
Claim 11
Dependent Claim
29 words
The device in accordance with claim 7 wherein said refractory metal layer comprises a refractory metal selected from the group consisting of tantalum, niobium, titanium, zirconium, chromium and hafnium.
Claim 12
Dependent Claim
17 words
The device in accordance with claim 8 wherein the refractory metal of said barrier layer comprises tantaium.
Claim 13
Dependent Claim
12 words
The device in accordance with claim 8 wherein said dopant comprises boron.
Claim 14
Dependent Claim
18 words
The device in accordance with claim 8 wherein the refractory metal of said refractory metal layer comprises titanium.
Claim 15
Dependent Claim
32 words
The device in accordance with claim 8 wherein the refractory metal of said barrier layer comprises tantalum, the dopant comprises boron and the refractory metal of said refractory metal layer comprises titanium.
Claim 16
Dependent Claim
93 words
In a semiconductory device comprising a silicon substrate containing a dopant and having a first refractory metal layer disposed on at least one portion of one surface thereof: (a) means for blocking transport of silicon from said substrate into said first refractory metal layer, said transport blocking means comprising a refractory metal nitride barrier layer disposed between said substrate and said first refractory metal layer; and (b) means for reducing contact resistance, said contact resistance reducing means comprising a second layer of refractory metal disposed between said barrier layer and said silicon substrate.
Claim 17
Dependent Claim
93 words
In a semiconductory device comprising a silicon substrate containing a dopant and having a first refractory metal layer disposed on at least one portion of one surface thereof: (a) means for blocking transport of silicon from said substrate into said first refractory metal layer, said transport blocking means comprising a refractory metal nitride barrier layer disposed between said substrate and said first refractory metal layer; and (b) means for reducing contact resistance, said contact resistance reducing means comprising a second layer of refractory metal disposed between said barrier layer and said silicon substrate.
Claim 18
Dependent Claim
30 words
The device in accordance with claim 13 wherein said second refractory metal layer comprises a refractory metal selected from the group consisting of tantalum, niobium, titanium, zirconium chromium and hafnium.
Claim 19
Dependent Claim
17 words
The device in accordance with claim 3 wherein the refractory metal of said barrier layer comprises tantalum.
Claim 20
Dependent Claim
12 words
The device in accordance with claim 3 wherein said dopant comprises boron.
Claim 21
Dependent Claim
32 words
The device in accordance with claim 3 wherein the refractory metal of said barrier layer comprises tantalum, the dopant comprises boron and the refractory metal of said refractory metal layer comprises titanium.
References Cited (Backward Citations)
US3614547A
Cited
US3879746A
Cited
US3877063A
Cited
DE2433299A1
Cited
US4164461A
Cited
US4180596A
Cited
US4141022A
Cited
DE2911484A1
Cited
US4228212A
Cited
JPS5680144A
Cited
US4344223A
Cited
US4446476A
Cited
US4451328A
Cited
US4556897A
Cited
US4570328A
Cited
JPS59181676A
Cited
US4545116A
Cited
US4566026A
Cited
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