US4214256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tantalum semiconductor contacts and method for fabricating same
Assignee: International Business Machines Corp
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Filing: 1978-09-08
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Granted: 1980-07-22
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Expires: 1998-09-08
Abstract
Abstract A silicon semiconductor device having contacts which include tantalum. The tantalum is useful in particular for fabricating Schottky barrier diodes having a low barrier height. The method includes: precleaning the silicon substrate prior to depositing the tantalum; depositing the tantalum at low pressure and low substrate temperature to avoid oxidation of the tantalum; and sintering the contact to reduce any interfacial charges and films remaining between the silicon and tantalum. When a metal which reacts with silicon during processing, such as aluminum, is used as interconnection metallurgy, a layer of chrome must be deposited between the tantalum and aluminum.
Inventors
- 👤 Hormazdyar M. Dalal
- 👤 Majid Ghafghaichi
- 👤 Lucian A. Kasprzak
- 👤 Hans Wimpfheimer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:33
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/64; H10D64/01; H10D64/012; H10D64/0121; H10W; H10W20/00; H10W20/40; H10W20/41; H10W20/425; Y; Y10; Y10S; Y10S148/00; Y10S148/139
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
38 words
A semiconductor contact comprising: a silicon semiconductor substrate; a layer of tantalum disposed atop said substrate; a layer of chrome containing chromium oxide disposed atop said tantalum layer; and a layer of aluminum disposed atop said chrome layer.
Claim 2
Dependent Claim
38 words
A semiconductor contact comprising: a silicon semiconductor substrate; a layer of tantalum disposed atop said substrate; a layer of chrome containing chromium oxide disposed atop said tantalum layer; and a layer of aluminum disposed atop said chrome layer.
Claim 3
Dependent Claim
20 words
A semiconductor contact as in claim 1 wherein said substrate exhibits N- type conductivity, thereby forming a Schottky barrier diode.
Claim 4
Dependent Claim
35 words
A semiconductor contact as in claim 1 wherein said substrate exhibits N+ conductivity and further comprising: a layer of metal silicide disposed between said layer of tantalum and said substrate, thereby forming an ohmic contact.
Claim 5
Dependent Claim
25 words
A semiconductor contact as in claim 1 wherein said tantalum layer is around 600 A thick and said chrome layer is around 800 A thick.
Claim 6
Dependent Claim
68 words
A Schottky barrier diode which exhibits a barrier height of around 0.5 electron volts comprising: a silicon semiconductor substrate having an N type impurity concentration of from 1×10 16 to 8×10 16 atoms per cm 3 ; a layer of tantalum disposed atop said substrate; and a layer of chrome containing chromium oxide disposed atop said tantalum layer; and a layer of aluminum disposed atop said chrome layer.
Claim 7
Dependent Claim
68 words
A Schottky barrier diode which exhibits a barrier height of around 0.5 electron volts comprising: a silicon semiconductor substrate having an N type impurity concentration of from 1×10 16 to 8×10 16 atoms per cm 3 ; a layer of tantalum disposed atop said substrate; and a layer of chrome containing chromium oxide disposed atop said tantalum layer; and a layer of aluminum disposed atop said chrome layer.
Claim 8
Dependent Claim
94 words
In an integrated circuit structure having ohmic and high-barrier-height Schottky barrier diode contacts which include metal silicide layers overlying N+ type silicon regions and first N- type silicon regions, respectively, and having low-barrier-height Schottky barrier diode contacts overlying second N- type silicon regions, the improvement wherein each of said contacts further comprise: a tantalum layer disposed atop each of said metal silicide layers and said second N- type silicon regions; a chrome containing chromium oxide layer disposed atop each of said tantalum layers; and an aluminum layer disposed atop each of said chrome layers.
Claim 9
Dependent Claim
94 words
In an integrated circuit structure having ohmic and high-barrier-height Schottky barrier diode contacts which include metal silicide layers overlying N+ type silicon regions and first N- type silicon regions, respectively, and having low-barrier-height Schottky barrier diode contacts overlying second N- type silicon regions, the improvement wherein each of said contacts further comprise: a tantalum layer disposed atop each of said metal silicide layers and said second N- type silicon regions; a chrome containing chromium oxide layer disposed atop each of said tantalum layers; and an aluminum layer disposed atop each of said chrome layers.
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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) | 1983-07-22 | 1984-01-21 | 1984-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-22 | 1988-01-21 | 1988-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-22 | 1992-01-21 | 1992-07-22 | $7700.00 | Window Closed / Lapsed |