US3714559A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of measuring magnetic fields utilizing a three dram igfet with particular bias
Assignee: Texas Instruments Inc
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Filing: 1971-08-10
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Granted: 1973-01-30
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Expires: 1991-08-10
Abstract
Abstract A mode of operation of a three-drain configured insulated gate field effect transistor which is extremely sensitive to magnetic fields is disclosed. The gate of the transistor is biased to a level less than transistor threshold, or alternatively, is connected to substrate ground. A first drain region opposite the source is biased to achieve avalanche breakdown of the junction. The other two drains are defined on either side of a line joining the source and first drain. These two drains are biased at a voltage below that required for avalanche of their junctions. In response to a magnetic field a voltage difference is generated across these two drains. In one embodiment of the invention, the region opposite the source is of a conductivity type the same as the substrate. In this configuration the detector does not require avalanche breakdown.
Inventors
- 👤 R Bate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:57
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/06; H; H10; H10D; H10D48/00; H10D48/40
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
120 words
A method for detecting a magnetic field comprising the steps of: a. biasing the gate electrode of a three-drain insulated gate field effect transistor structure having one drain opposite the source and the other two drains spaced on opposite sides of a line joining the source and said one drain, to a potential less than that required to invert the semiconductor material thereunder; b. biasing said one drain to effect avalanche; c. biasing said other two drains to a value below that required for avalanche; d. measuring the voltage between said other two drains whereby in response to an applied magnetic field the change in magnitude of said measured voltage is proportional to the strength of said applied magnetic field.
Claim 2
Independent Claim
120 words
A method for detecting a magnetic field comprising the steps of: a. biasing the gate electrode of a three-drain insulated gate field effect transistor structure having one drain opposite the source and the other two drains spaced on opposite sides of a line joining the source and said one drain, to a potential less than that required to invert the semiconductor material thereunder; b. biasing said one drain to effect avalanche; c. biasing said other two drains to a value below that required for avalanche; d. measuring the voltage between said other two drains whereby in response to an applied magnetic field the change in magnitude of said measured voltage is proportional to the strength of said applied magnetic field.
Claim 3
Independent Claim
120 words
A method for detecting a magnetic field comprising the steps of: a. biasing the gate electrode of a three-drain insulated gate field effect transistor structure having one drain opposite the source and the other two drains spaced on opposite sides of a line joining the source and said one drain, to a potential less than that required to invert the semiconductor material thereunder; b. biasing said one drain to effect avalanche; c. biasing said other two drains to a value below that required for avalanche; d. measuring the voltage between said other two drains whereby in response to an applied magnetic field the change in magnitude of said measured voltage is proportional to the strength of said applied magnetic field.
Claim 4
Independent Claim
120 words
A method for detecting a magnetic field comprising the steps of: a. biasing the gate electrode of a three-drain insulated gate field effect transistor structure having one drain opposite the source and the other two drains spaced on opposite sides of a line joining the source and said one drain, to a potential less than that required to invert the semiconductor material thereunder; b. biasing said one drain to effect avalanche; c. biasing said other two drains to a value below that required for avalanche; d. measuring the voltage between said other two drains whereby in response to an applied magnetic field the change in magnitude of said measured voltage is proportional to the strength of said applied magnetic field.
Claim 5
Dependent Claim
22 words
A method for detecting a magnetic field as set forth in claim 1 wherein said gate electrode is connected to circuit ground.
Claim 6
Dependent Claim
145 words
In a structure comprising a semiconductor substrate of one conductivity type having first, second, third and fourth spaced apart pockets of opposite conductivity type material extending to one surface thereof, said third and fourth pockets being defined on opposite sides of a line joining said first and second pockets, the method of detecting a magnetic field comprising the steps of: a. connecting said first pocket to circuit ground; b. biasing said second pocket to a voltage level sufficient to cause avalanche breakdown of the p-n junction between said second pocket and said substrate; c. biasing said third and fourth pockets to a voltage level less than that required to produce avalanche breakdown of their respective p-n junctions with said substrate; and d. measuring the voltage difference across said third and fourth pockets to obtain an output proportional to the strength of an applied magnetic field.
Claim 7
Dependent Claim
145 words
In a structure comprising a semiconductor substrate of one conductivity type having first, second, third and fourth spaced apart pockets of opposite conductivity type material extending to one surface thereof, said third and fourth pockets being defined on opposite sides of a line joining said first and second pockets, the method of detecting a magnetic field comprising the steps of: a. connecting said first pocket to circuit ground; b. biasing said second pocket to a voltage level sufficient to cause avalanche breakdown of the p-n junction between said second pocket and said substrate; c. biasing said third and fourth pockets to a voltage level less than that required to produce avalanche breakdown of their respective p-n junctions with said substrate; and d. measuring the voltage difference across said third and fourth pockets to obtain an output proportional to the strength of an applied magnetic field.
References Cited (Backward Citations)
US3448353A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-30 | 1976-07-31 | 1977-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-30 | 1980-07-31 | 1981-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-30 | 1984-07-31 | 1985-01-30 | $7700.00 | Window Closed / Lapsed |