US4478881A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tungsten barrier contact
Assignee: Solid State Devices Inc
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Filing: 1981-12-28
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Granted: 1984-10-23
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Expires: 2001-12-28
Abstract
Abstract A semiconductor contact has a thin barrier layer less than 500 angstroms in thickness of a metal such as tungsten applied between an aluminum contact layer and a metal-semiconductor compound. The metal semiconductor compound forms a junction with an underlying semiconductor substrate. The thin barrier prevents a chemical reaction between the aluminum of the contact layer and the metal of the metal-semiconductor compound.
Inventors
- 👤 Meir Bartur
- 👤 Marc Nicolet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:16
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/64; H10D62/00; H10D62/80; H10D62/83; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10D64/012; H10D64/0121; H10D64/62; Y; Y10; Y10S; Y10S438/00; Y10S438/907
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
107 words
A method of fabricating a semiconductor device comprising the steps of: depositing a first metal layer onto a silicon substrate; depositing a second metal layer onto the first metal layer, selected from the group consisting of tungsten, tantalum and hafnium; depositing an aluminum contact onto the second metal layer; and thereafter heating the substrate and metal layers on the substrate concurrently to anneal the first metal layer and the silicon substrate to form a silicide and also to sinter the aluminum contact in a single step, wherein the second metal layer prevents the aluminum from chemically reacting with the silicide during the single annealing and sintering step.
Claim 2
Independent Claim
107 words
A method of fabricating a semiconductor device comprising the steps of: depositing a first metal layer onto a silicon substrate; depositing a second metal layer onto the first metal layer, selected from the group consisting of tungsten, tantalum and hafnium; depositing an aluminum contact onto the second metal layer; and thereafter heating the substrate and metal layers on the substrate concurrently to anneal the first metal layer and the silicon substrate to form a silicide and also to sinter the aluminum contact in a single step, wherein the second metal layer prevents the aluminum from chemically reacting with the silicide during the single annealing and sintering step.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein the second metal layer is deposited in a layer having a thickness which is less than 500 angstroms.
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein each of the metal layers is deposited by evaporation utilizing an electron beam gun.
Claim 5
Dependent Claim
26 words
The method of claim 1 wherein the first metal layer deposited is nickel so that a nickel silicide is formed during the annealing and sintering step.
Claim 6
Independent Claim
98 words
A method of fabricating a semiconductor device comprising the steps of: depositing a layer of nickel onto a silicon substrate; depositing a layer of tungsten having a thickness of less than 500 angstroms on the nickel layer; depositing a contact layer of aluminum onto the tungsten; heating the substrate and metal layers in a furnace to anneal the nickel and silicon to form a nickel silicide and also to sinter the aluminum contact wherein the tungsten layer prevents the aluminum from chemically reacting with the nickel silicide and the annealing and sintering are performed in a single step.
Claim 7
Independent Claim
98 words
A method of fabricating a semiconductor device comprising the steps of: depositing a layer of nickel onto a silicon substrate; depositing a layer of tungsten having a thickness of less than 500 angstroms on the nickel layer; depositing a contact layer of aluminum onto the tungsten; heating the substrate and metal layers in a furnace to anneal the nickel and silicon to form a nickel silicide and also to sinter the aluminum contact wherein the tungsten layer prevents the aluminum from chemically reacting with the nickel silicide and the annealing and sintering are performed in a single step.
Claim 8
Independent Claim
112 words
A method of fabricating a semiconductor device comprising the steps of: depositing three sequential metal layers of nickel, tungsten and aluminum on a silicon substrate by evaporation in a depressurized electron beam gun chamber while maintaining the depressurization of the chamber between depositions; and heating the substrate in a furnace to anneal the nickel and silicon into nickel silicide and to concurrently sinter the aluminum to provide an electrical contact wherein the tungsten layer provides an electrical connection between the aluminum contact and the nickel silicide region and also prevents a chemical reaction between the nickel and the aluminum so that the nickel silicide will form rather than a nickel aluminum compound.
Claim 9
Independent Claim
112 words
A method of fabricating a semiconductor device comprising the steps of: depositing three sequential metal layers of nickel, tungsten and aluminum on a silicon substrate by evaporation in a depressurized electron beam gun chamber while maintaining the depressurization of the chamber between depositions; and heating the substrate in a furnace to anneal the nickel and silicon into nickel silicide and to concurrently sinter the aluminum to provide an electrical contact wherein the tungsten layer provides an electrical connection between the aluminum contact and the nickel silicide region and also prevents a chemical reaction between the nickel and the aluminum so that the nickel silicide will form rather than a nickel aluminum compound.
Claim 10
Independent Claim
81 words
A method of fabricating a semiconductor device comprising the steps of: depositing a first metal layer for forming a metal silicide layer onto a silicon substrate in a depressurized chamber; depositing a second metal layer onto the first layer in the depressurized chamber, said second layer being selected from the group consisting of tungsten, tantalum and hafnium; and depositing an aluminum contact onto the second metal layer in the depressurized chamber; wherein the depressurization of the chamber is maintained between depositions.
Claim 11
Independent Claim
81 words
A method of fabricating a semiconductor device comprising the steps of: depositing a first metal layer for forming a metal silicide layer onto a silicon substrate in a depressurized chamber; depositing a second metal layer onto the first layer in the depressurized chamber, said second layer being selected from the group consisting of tungsten, tantalum and hafnium; and depositing an aluminum contact onto the second metal layer in the depressurized chamber; wherein the depressurization of the chamber is maintained between depositions.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-23 | 1988-04-23 | 1988-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-23 | 1992-04-23 | 1992-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-23 | 1996-04-23 | 1996-10-23 | $7700.00 | Window Closed / Lapsed |