US3648129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Insulated gate field effect transistor with integrated safety diode
Assignee: US Philips Corp
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Filing: 1969-04-23
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Granted: 1972-03-07
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Expires: 1989-04-23
Abstract
Abstract An insulated gate field effect transistor with an integrated safety diode is described. The safety diode comprises oppositetype conductivity diode zones forming a low breakdown voltage PNjunction by reason of high dopant concentrations in the diode zones. The diode zone which is of the same type conductivity as the substrate completely surrounds the other diode zone and can thus serve as a channel interrupter preventing parasitic transistor action between the safety diode and the active zones of the field effect transistor. Other features include location of the diode zone of the same type conductivity as the substrate contiguous with the source electrode, and a metal layer on the surface short circuiting the PN-junction therebetween to directly connect the source to one of the zones of the safety diode.
Inventors
- 👤 Rijkent Jan Nienhuis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:02
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/52; H03F1/523; H03K; H03K17/00; H03K17/08; H03K17/081; H03K17/0812; H03K17/08122; H10; H10D; H10D84/00; H10D84/80; H10D84/811; H10D89/00; H10D89/60; H10D89/601; H10D89/611; H10W; H10W72/00; H10W72/90; H10W72/921; H10W72/926
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
245 words
An insulated gate field effect transistor comprising a semiconductor substrate of one type conductivity having a surface, two adjacent surface electrode zones of the opposite type conductivity in the substrate to constitute source and drain electrodes, an insulating layer on the surface, a gate electrode on the insulating layer and overlying a substrate portion between the source and drain electrode zones, a safety diode located in the substrate and comprising a first diode zone adjacent the surface and of the opposite type conductivity and a second diode zone of the one type conductivity and having at least a part adjacent the surface and forming a PN-junction with the first diode zone, the impurity concentration in the first and second diode zones being higher than that of the substrate and such that the said PN-junction between the diode zones has a breakdown voltage not exceeding 15 volts, the second diode zone at said surface completely surrounding the first diode zone, means electrically coupling the gate electrode to the first diode zone, said first and second diode zones being laterally spaced from and outside of the source and drain elecTrode zones, one of said source and drain electrodes zones having an extension completely surrounding the second diode zone and forming a PN-junction therewith, and metallization means on the semiconductor surface providing a direct electrical connection between the second diode zone and said one of the source and drain electrode zones and substantially surrounding said first diode zone.
Claim 2
Dependent Claim
245 words
An insulated gate field effect transistor comprising a semiconductor substrate of one type conductivity having a surface, two adjacent surface electrode zones of the opposite type conductivity in the substrate to constitute source and drain electrodes, an insulating layer on the surface, a gate electrode on the insulating layer and overlying a substrate portion between the source and drain electrode zones, a safety diode located in the substrate and comprising a first diode zone adjacent the surface and of the opposite type conductivity and a second diode zone of the one type conductivity and having at least a part adjacent the surface and forming a PN-junction with the first diode zone, the impurity concentration in the first and second diode zones being higher than that of the substrate and such that the said PN-junction between the diode zones has a breakdown voltage not exceeding 15 volts, the second diode zone at said surface completely surrounding the first diode zone, means electrically coupling the gate electrode to the first diode zone, said first and second diode zones being laterally spaced from and outside of the source and drain elecTrode zones, one of said source and drain electrodes zones having an extension completely surrounding the second diode zone and forming a PN-junction therewith, and metallization means on the semiconductor surface providing a direct electrical connection between the second diode zone and said one of the source and drain electrode zones and substantially surrounding said first diode zone.
Claim 3
Dependent Claim
82 words
An insulated gate field effect transistor as set forth in claim 1 wherein the second diode zone is contiguous with said one of the source and drain electrode zones forming a PN-junction that extends to the surface, and the metallization means comprises a conductor provided on the surface through a hole in the insulator and covering at least the part of the junction adjacent said one electrode zone and short circuiting the said junction part to provide the said direct electrical connection.
Claim 4
Dependent Claim
29 words
An insulated gate field effect transistor as set forth in claim 1 wherein the said one electrode zone is the source, and the source and drain zones are annular.
Claim 5
Dependent Claim
82 words
An insulated gate field effect transistor as set forth in claim 1 wherein the safety diode comprises a third diode zone of the one type conductivity inset in and completely surrounded by the first diode zone and forming a PN-junction therebetween, said third diode zone having a higher impurity concentration than that of the substrate and such that the last-mentioned PN-junction has a breakdown voltage not exceeding 15 volts, and means are provided connecting the gate electrode to the third diode zone.
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) | 1975-03-07 | 1975-09-06 | 1976-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-07 | 1979-09-06 | 1980-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-07 | 1983-09-06 | 1984-03-07 | $7700.00 | Window Closed / Lapsed |