Patent US4307132A successfully refreshed from Google Patents.
US4307132A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for fabricating a contact on a semiconductor substrate by depositing an aluminum oxide diffusion barrier layer
Assignee: International Business Machines Corp
•
Filing: 1979-11-07
•
Granted: 1981-12-22
•
Expires: 1999-11-07
Abstract
Abstract Thin film structures comprising a layer of aluminum and a material having a tendency to interact with aluminum are separated by an intermediate layer of aluminum having a high aluminum oxide content. The intermediate layer prevents said interaction by acting as a diffusion barrier. Preferred embodiments are directed to silicon semiconductor metallization structures, including Schottky barrier contacts, which comprise a bottom layer of tantalum, or other transition metal, or a metal silicide in contact with a silicon substrate, an intermediate layer of aluminum having a high aluminum oxide content and a top layer of aluminum. The intermediate layer functions as a diffusion barrier between aluminum and the metal, metal silicide or silicon. The preferred embodiments of the invention also includes the process for forming such structures preferably comprising: depositing pure tantalum under high vacuum in evaporation apparatus, substituting aluminum for tantalum in the evaporation apparatus and bleeding-in water, air or oxygen to form the aluminum oxide-rich intermediate aluminum layer and then returning to the high vacuum to deposit pure aluminum. The invention is also applicable to FET or CCD structures where a diffusion barrier for aluminum is required.
Inventors
- 👤 Wei-Kan Chu
- 👤 James K. Howard
- 👤 James F. White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:51
CPC Classifications
H; H10; H10W; H10W72/00; H10W72/01; H10W72/012; H10D; H10D64/00; H10D64/01; H10D64/012; H10D64/0121; H10W20/00; H10W20/01; H10W20/031; H10W20/032; H10W20/40; H10W20/41; H10W20/425; H10W72/20; H10W72/251; H10W72/90; H10W72/921; H10W72/923; H10W72/951; H10W72/952
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
84 words
A method for fabricating a contact on a silicon semi-conductor substrate comprising: depositing a transition metal layer upon a portion of said substrate in a vacuum chamber at a low pressure so as to avoid oxidation of said transition metal layer; depositing an intermediate layer of aluminum having an aluminum oxide content sufficient to provide an effective barrier to the diffusion of aluminum into said transition metal layer upon said transition metal layer; and depositing an upper layer of aluminum atop said intermediate layer.
Claim 2
Independent Claim
84 words
A method for fabricating a contact on a silicon semi-conductor substrate comprising: depositing a transition metal layer upon a portion of said substrate in a vacuum chamber at a low pressure so as to avoid oxidation of said transition metal layer; depositing an intermediate layer of aluminum having an aluminum oxide content sufficient to provide an effective barrier to the diffusion of aluminum into said transition metal layer upon said transition metal layer; and depositing an upper layer of aluminum atop said intermediate layer.
Claim 3
Dependent Claim
41 words
A method as in claim 1 further comprising the step of: depositing an intermediate layer of a transition metal having a high transition metal oxide content between said transition metal and said intermediate layer of aluminum having an aluminum oxide content.
Claim 4
Dependent Claim
21 words
A method as in claim 2 wherein said depositing steps are selected from the group consisting of evaporation and RF sputtering.
Claim 5
Dependent Claim
27 words
A method as in claim 1 wherein said upper layer of aluminum is in direct contact with said intermediate layer of aluminum having an aluminum oxide content.
Claim 6
Dependent Claim
21 words
A method as in claim 1 wherein said depositing setups are selected from the group consisting of evaporation and RF sputtering.
Claim 7
Dependent Claim
23 words
A method as in claim 1 wherein said transition metal is selected from the group consisting of tantalum, zirconium, hafnium, titanium and nickel.
Claim 8
Independent Claim
112 words
A method for fabricating a contact on a silicon semiconductor substrate comprising: evaporating a first transition metal layer upon at least a selected portion of said substrate while maintaining a low pressure in a vacuum chamber so as to avoid oxidation of said transition metal; evaporating a layer of aluminum upon said first transition metal layer at increased pressure within said chamber so as to deposit an intermediate layer of aluminum having an aluminum oxide content sufficient to provide an effective barrier to the diffusion of aluminum into said transition metal layer atop said first transition metal layer; and evaporating an upper layer of aluminum at reduced pressure atop said intermediate layer.
Claim 9
Independent Claim
112 words
A method for fabricating a contact on a silicon semiconductor substrate comprising: evaporating a first transition metal layer upon at least a selected portion of said substrate while maintaining a low pressure in a vacuum chamber so as to avoid oxidation of said transition metal; evaporating a layer of aluminum upon said first transition metal layer at increased pressure within said chamber so as to deposit an intermediate layer of aluminum having an aluminum oxide content sufficient to provide an effective barrier to the diffusion of aluminum into said transition metal layer atop said first transition metal layer; and evaporating an upper layer of aluminum at reduced pressure atop said intermediate layer.
Claim 10
Dependent Claim
23 words
A method as in claim 7 wherein said transition metal is selected from the group consisting of tantalum, zirconium, hafnium, titanium and nickel.
Claim 11
Dependent Claim
46 words
A method as in claim 7 wherein said first transition metal layer is tantalum, the thickness of said first tantalum layer is around 1000 A, and the thickness of said intermediate layer of aluminum having a high aluminum oxide content is less than around 1000 A.
Claim 12
Dependent Claim
65 words
A method as in claim 7 further comprising the step of: evaporating a second layer of said transition metal atop said first transition metal layer at increased pressure so as to form an intermediate layer of said transition metal having a high transition metal oxide content, said evaporation being done prior to the evaporation of said intermediate layer of aluminum having an aluminum oxide content.
Claim 13
Dependent Claim
61 words
A method as in claim 10 wherein said transition metal is tantalum, the thickness of said first tantalum layer is around 1000 A; the thickness of said intermediate layer of tantalum having a high tantalum oxide content is around 200 A; and the thickness of said intermediate layer of aluminum having an aluminum oxide content is less than around 1000 A.
References Cited (Backward Citations)
US3106489A
Cited
US3417301A
Cited
US3809627A
Cited
US3568014A
Cited
US3641402A
Cited
US3862017A
Cited
US3878442A
Cited
US3716469A
Cited
US3939047A
Cited
US3806778A
Cited
US3983284A
Cited
US3906540A
Cited
US3886580A
Cited
US3864217A
Cited
US4215156A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-21 | 1985-06-22 | 1985-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-21 | 1989-06-22 | 1989-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-21 | 1993-06-22 | 1993-12-22 | $7700.00 | Window Closed / Lapsed |