US3717516A
Expired / Lapsed
US
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Methods of controlling the reverse breakdown characteristics of semiconductors, and devices so formed
Assignee: AT&T Inc
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Filing: 1970-10-23
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Granted: 1973-02-20
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Expires: 1990-10-23
Abstract
Abstract The impurity density profile of p-n junctions in semiconductive devices is modified at localized regions of the junctions. This is achieved by a controlled oxidation process that causes a selective redistribution of impurities at such regions of the junctions. The process is particularly useful in the manufacture of reverse bias regulator diodes since it enables a controlled adjustment of the breakdown voltage with considerable precision. When the process is used in the manufacture of low voltage regulators, sharp reverse voltage breakdowns and other desirable electrical properties are obtained.
Inventors
- 👤 A Hatcher
- 👤 R Stonefelt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:18
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; H10P14/6309; H10D; H10D99/00; H10P14/6322; Y; Y10; Y10S; Y10S148/00; Y10S148/049; Y10S148/144; Y10S438/00; Y10S438/914; Y10S438/92
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
107 words
A method of producing a semiconductor device, which comprises the steps of: establishing a p-n junction with a first impurity-density profile in a semiconductor body such that a major portion of the junction is further than 1 fringe from a surface of the body but such that the junction intersects said surface; and oxidizing the surface of the body which the junction intersects to modify the impurity-density profile of the junction in the region of the intersection whereby a p-n junction is produced having a major portion of its area with a first impurity-density profile and a minor portion of its area with a modified impurity-density profile.
Claim 2
Independent Claim
107 words
A method of producing a semiconductor device, which comprises the steps of: establishing a p-n junction with a first impurity-density profile in a semiconductor body such that a major portion of the junction is further than 1 fringe from a surface of the body but such that the junction intersects said surface; and oxidizing the surface of the body which the junction intersects to modify the impurity-density profile of the junction in the region of the intersection whereby a p-n junction is produced having a major portion of its area with a first impurity-density profile and a minor portion of its area with a modified impurity-density profile.
Claim 3
Dependent Claim
16 words
A new method according to claim 1 wherein the n-type impurity is phosphorus, arsenic or antimony.
Claim 4
Dependent Claim
17 words
A new method according to claim 1 wherein the p-type impurity is boron, aluminum, gallium or indium.
Claim 5
Dependent Claim
35 words
The method of claim 1 wherein the modification of the impurity-density profile produces a reverse breakdown voltage of the semiconductor device of less than about 8 volts and produces a junction having a sharp knee.
Claim 6
Dependent Claim
15 words
A new method according to claim 1 wherein the semiconductive body is comprised of silicon.
Claim 7
Dependent Claim
18 words
A method according to claim 5 wherein the n-type impurity is antimony and the p-type impurity is boron.
Claim 8
Independent Claim
196 words
A method of producing a semiconductor device, which comprises the steps of: preparing a slice of semiconductive material comprised of an intrinsic semiconductor and a high concentration of a first conductivity-type determining impurity; forming an oxide film on a surface of the slice; generating a first opening in the oxide film; diffusing a second impurity through said first opening of opposite conductivity type than the first impurity into the slice to form a p-n junction with a first impurity-density profile such that a major portion of the junction is further than one fringe from said surface and such that the junction intersects said surface of the slice; oxidizing said surface to modify the impurity-density profile of the junction in the region of the intersection to form an annular region having a reverse breakdown characteristic with a sharp knee; generating a second opening in the oxide film within the bounds of said annular region; and depositing a metallic contact onto the slice through said second opening with the outer portion of the metallic contact being at least one mil from the annular region whereby the functioning of said region is unaffected by the metal of the contact.
Claim 9
Independent Claim
196 words
A method of producing a semiconductor device, which comprises the steps of: preparing a slice of semiconductive material comprised of an intrinsic semiconductor and a high concentration of a first conductivity-type determining impurity; forming an oxide film on a surface of the slice; generating a first opening in the oxide film; diffusing a second impurity through said first opening of opposite conductivity type than the first impurity into the slice to form a p-n junction with a first impurity-density profile such that a major portion of the junction is further than one fringe from said surface and such that the junction intersects said surface of the slice; oxidizing said surface to modify the impurity-density profile of the junction in the region of the intersection to form an annular region having a reverse breakdown characteristic with a sharp knee; generating a second opening in the oxide film within the bounds of said annular region; and depositing a metallic contact onto the slice through said second opening with the outer portion of the metallic contact being at least one mil from the annular region whereby the functioning of said region is unaffected by the metal of the contact.
Claim 10
Dependent Claim
46 words
A new method according to claim 7 wherein the oxidation to form the annular region is continued for a time sufficient to reduce the breakdown voltage to a value less than about 8 volts and the breakdown impedance to a value less than about 4 ohms.
Claim 11
Dependent Claim
23 words
A new method according to claim 7 wherein the first impurity is an n-type impurity and the second impurity is a p-type impurity.
Claim 12
Dependent Claim
12 words
A method according to claim 9 wherein the first impurity is antimony.
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) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |