Patent US3940783A successfully refreshed from Google Patents.
US3940783A
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Majority carriers-variable threshold rectifier and/or voltage reference semiconductor structure
Assignee: Signetics Corp
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Filing: 1974-02-11
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Granted: 1976-02-24
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Expires: 1994-02-11
Abstract
Abstract A majority charge carrier semiconductor structure including a relatively heavily doped n type support layer, a second n type layer formed on the support layer and having a relatively light doping, a p layer formed on the second n layer, and a third n type layer having a relatively heavy doping formed atop the p layer. When voltage means is applied between top and support layers principal current flow is by majority charge carriers in either direction determined by the polarity of a pre-determined voltage. Current flow occurs substantially below the critical electric field, and free of avalanche multiplication or tunneling. In alternate embodiments the doping impurity concentration may be varied to alternately provide a device wherein the magnitude of voltage reference which determines current flow in one direction or in the opposite direction may be symmetrical, asymmetrical or highly asymmetrical.
Inventors
- 👤 Bohumil Polata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:32
CPC Classifications
H; H10; H10D; H10D8/00; H10D8/825; H10D99/00; H10W; H10W90/00; Y; Y10; Y10S; Y10S148/00; Y10S148/085
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
285 words
A rectifier and reference structure utilizing majority charge carriers comprising: a one-conductivity support layer and means for making electrical contact to said support layer, a second one-conductivity layer having a concentration differing from and carried by the support layer, an opposite-conductivity layer carried by the second layer to form a first junction, a third one-conductivity layer carried atop the opposite-conductivity layer to form a second junction and means for making electrical contact to said third layer, said opposite-conductivity layer having a decreasing impurity concentration from said second junction to said first junction wherein the second one-conductivity, opposite-conductivity, and third one-conductivity layer impurity concentrations and the opposite-conductivity layer thickness are selected to form a first depletion region at said first junction, so that when voltage means of one polarity is applied between said contacts said structure opposes current flow until a voltage magnitude is reached which causes said first depletion region to extend through the predetermined thickness of the opposite conductivity layer to intercouple said second and third one-conductivity layers, said impurity concentrations being further selected to provide said first depletion region intercoupling before avalanche and Zener breakdown of said first junction, and wherein said one-conductivity, opposite-conductivity and third one-conductivity layers have impurity concentrations further selected to form a second depletion region at said second junction, so that when voltage means of opposite polarity is applied between said contacts said structure opposes current flow until a voltage magnitude is reached which causes said second depletion region to extend through said predetermined thickness of the opposite-conductivity layer to intercouple said second and third one-conductivity layers, said impurity concentrations being further selected to provide said second depletion region intercoupling before avalanche and Zener breakdown of said second junction.
Claim 2
Dependent Claim
285 words
A rectifier and reference structure utilizing majority charge carriers comprising: a one-conductivity support layer and means for making electrical contact to said support layer, a second one-conductivity layer having a concentration differing from and carried by the support layer, an opposite-conductivity layer carried by the second layer to form a first junction, a third one-conductivity layer carried atop the opposite-conductivity layer to form a second junction and means for making electrical contact to said third layer, said opposite-conductivity layer having a decreasing impurity concentration from said second junction to said first junction wherein the second one-conductivity, opposite-conductivity, and third one-conductivity layer impurity concentrations and the opposite-conductivity layer thickness are selected to form a first depletion region at said first junction, so that when voltage means of one polarity is applied between said contacts said structure opposes current flow until a voltage magnitude is reached which causes said first depletion region to extend through the predetermined thickness of the opposite conductivity layer to intercouple said second and third one-conductivity layers, said impurity concentrations being further selected to provide said first depletion region intercoupling before avalanche and Zener breakdown of said first junction, and wherein said one-conductivity, opposite-conductivity and third one-conductivity layers have impurity concentrations further selected to form a second depletion region at said second junction, so that when voltage means of opposite polarity is applied between said contacts said structure opposes current flow until a voltage magnitude is reached which causes said second depletion region to extend through said predetermined thickness of the opposite-conductivity layer to intercouple said second and third one-conductivity layers, said impurity concentrations being further selected to provide said second depletion region intercoupling before avalanche and Zener breakdown of said second junction.
Claim 3
Dependent Claim
47 words
A structure as in claim 1 wherein said second one-conductivity, opposite conductivity and third one-conductivity layer impurity concentrations and said opposite-conductivity layer thickness are selected to provide a symmetrical current flow characteristic when voltage means is applied for equal voltage magnitudes of respective one and opposite polarities.
Claim 4
Dependent Claim
54 words
A semiconductor structure as in claim 1 wherein said second one-conductivity, opposite-conductivity, and third one-conductivity layer impurity concentrations and the opposite-conductivity region thickness are selected to provide an asymmetrical current flow characteristic when a first voltage magnitude of one polarity is applied and when a second voltage magnitude of opposite polarity is alternately applied.
Claim 5
Dependent Claim
97 words
A semiconductor structure as in claim 3 wherein said one-conductivity support layer has a thickness of approximately 11/3 microns and an impurity concentration of approximately 2×10 19 impurity atoms/cm. 3 , said second one-conductivity layer has a thickness of approximately 4 microns and an impurity concentration of 8×10 14 impurity atoms/cm. 3 , said opposite-conductivity layer has a thickness of approximately 1 micron and an impurity concentration of 4×10 16 impurity atoms/cm. 3 and said third one-conductivity layer has a thickness of approximately 1 2/3 microns and an impurity concentration of 8×10 19 impurity atoms/cm. 3 .
Claim 6
Dependent Claim
32 words
A semiconductor structure as in claim 1 wherein said opposite-conductivity decreases from approximately 2×10 17 impurity atoms/cm. 3 at said second junction to approximately 4×10 14 impurity atoms/cm. 3 at first junction.
Claim 7
Dependent Claim
220 words
A rectifier and reference structure utilizing majority charge carriers and having first and second PN junctions comprising: a p type substrate having a surface, an n+ region formed in the substrate extending to said surface, an n- epitaxial layer formed on the upper surface of said substrate, a p+ isolation ring extending downward from the upper surface of said epitaxial layer to contact said p type substrate, said isolation ring positioned beyond the outer periphery of said n+ region, to form an n- enclosed epitaxial region, an n+ region extending downward from the upper surface of said layer to contact said n+ buried region formed in said substrate, a p+-region formed in the enclosed epitaxial region extending to the surface forming a second junction therewith having a corresponding depletion region, an n++ region formed and extending to the surface to form a first junction therewith having a corresponding depletion region, said p+-region having a decreasing impurity concentration from said second junction to said first junction, ohmic contacts to the exposed n++ and n+ region upper surfaces so that when voltage means of either one or the opposite polarity is applied between said contacts said structure opposes current flow until the voltage magnitude causes the corresponding depletion region to extend through said p+-layer to intercouple said n- layer and n++ region.
Claim 8
Dependent Claim
220 words
A rectifier and reference structure utilizing majority charge carriers and having first and second PN junctions comprising: a p type substrate having a surface, an n+ region formed in the substrate extending to said surface, an n- epitaxial layer formed on the upper surface of said substrate, a p+ isolation ring extending downward from the upper surface of said epitaxial layer to contact said p type substrate, said isolation ring positioned beyond the outer periphery of said n+ region, to form an n- enclosed epitaxial region, an n+ region extending downward from the upper surface of said layer to contact said n+ buried region formed in said substrate, a p+-region formed in the enclosed epitaxial region extending to the surface forming a second junction therewith having a corresponding depletion region, an n++ region formed and extending to the surface to form a first junction therewith having a corresponding depletion region, said p+-region having a decreasing impurity concentration from said second junction to said first junction, ohmic contacts to the exposed n++ and n+ region upper surfaces so that when voltage means of either one or the opposite polarity is applied between said contacts said structure opposes current flow until the voltage magnitude causes the corresponding depletion region to extend through said p+-layer to intercouple said n- layer and n++ region.
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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) | 1979-02-23 | 1979-08-25 | 1980-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-23 | 1983-08-25 | 1984-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-23 | 1987-08-25 | 1988-02-24 | $7700.00 | Window Closed / Lapsed |