US3975648A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flat-band voltage reference
Assignee: HP Inc
•
Filing: 1975-06-16
•
Granted: 1976-08-17
•
Expires: 1995-06-16
Abstract
Abstract A flat-band voltage reference includes two insulated-gate field-effect transistors, hereinafter IGFETs, which are substantially identical except for their flat-band voltage characteristics and which are biased to carry equal drain currents at equal drain voltages. The resulting difference in potential between the gate contacts of the IGFETs produces a voltage reference which is substantially independent of variances in operating points, supply potentials, and temperature.
Inventors
- 👤 Morley C. Tobey, Jr.
- 👤 David J. Giuliani
- 👤 Peter B. Ashkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:16
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/64; G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/24; G05F3/242; G05F3/245; G05F3/247
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
74 words
A voltage reference comprising: first and second field-effect devices, each having a source contact, a drain contact, and a gate contact and each device having a different flat-band voltage characteristic from the other; means coupled to the first and second field-effect devices for producing substantially identical current flow to the drain contacts of the first and second field-effect devices; and means for coupling to the gate contacts of the first and second field-effect devices.
Claim 2
Dependent Claim
74 words
A voltage reference comprising: first and second field-effect devices, each having a source contact, a drain contact, and a gate contact and each device having a different flat-band voltage characteristic from the other; means coupled to the first and second field-effect devices for producing substantially identical current flow to the drain contacts of the first and second field-effect devices; and means for coupling to the gate contacts of the first and second field-effect devices.
Claim 3
Dependent Claim
66 words
A voltage reference as in claim 1 wherein the first and second field-effect devices have substrates of substantially similar semiconductor material, the first field-effect device has a first gate field plate of a first metal and the second field-effect device has a second gate field plate of a second metal for producing different respective metal to semiconductor work-function differences in the first and second field-effect devices.
Claim 4
Dependent Claim
83 words
A voltage reference as in claim 1 wherein the first and second field-effect devices have substrates of a first semiconductor material, a gate field plate of the first-effect device is of a second semiconductor material and a gate field plate of the second field-effect device is of a third semiconductor material, the first and second semiconductor materials in combination producing a semiconductor to semiconductor work-function difference which is different from the semiconductor to semiconductor work-function difference of the first and third semiconductor materials.
Claim 5
Dependent Claim
50 words
A voltage reference as in claim 1 wherein the first and second field-effect devices have similar semiconductor substrates, the first field-effect device has a gate field plate made of a material including semiconductor material and the second field-effect device has a gate field plate made of material including a metal.
Claim 6
Dependent Claim
29 words
A voltage reference as in claim 1 wherein the first field-effect device has a first interface state density and the second field-effect device has a second interface state density.
Claim 7
Dependent Claim
63 words
A voltage reference as in claim 1 wherein the first field-effect device has a semiconductor substrate coupled to an insulator and a first fixed charge per unit area located at its semiconductor to insulator interface and the second field-effect device has a semiconductor substrate coupled to an insulator and a second fixed charge per unit area located at its semiconductor to insulator interface.
Claim 8
Dependent Claim
33 words
A voltage reference as in claim 1 wherein the first field-effect device has a insulator with a first charge distribution and the second field-effect device has an insulator with a second charge distribution.
Claim 9
Dependent Claim
72 words
A voltage reference as in claim 1 wherein the first field-effect device has a semiconductor substrate and multiple insulators, the insulator contacting the semiconductor substrate of the first field-effect device being sufficiently thin to permit tunneling; and bias means coupled to the gate contact of the first field-effect device for tunneling charge into the first field-effect device and producing a difference between flat-band voltage characteristics of the first and second field-effect devices.
Claim 10
Dependent Claim
31 words
A voltage reference as in claim 8 wherein the second field-effect device has multiple insulators, the insulator contacting the semiconductor of the second field-effect device being sufficiently thin to permit tunneling.
Claim 11
Dependent Claim
50 words
A voltage reference as in claim 8 wherein the first field-effect device has a silicon substrate, a first insulator of silicon dioxide in contact with the silicon substrate and a second insulator of silicon nitride in contact with the first insulator and the gate contact of the first field-effect device.
Claim 12
Dependent Claim
50 words
A voltage reference as in claim 10 wherein the second field-effect device has a silicon substrate, a first insulator of silicon dioxide in contact with the silicon substrate and a second insulator of silicon nitride in contact with the first insulator and the gate contact of the second field-effect device.
Claim 13
Dependent Claim
79 words
A voltage reference comprising: first and second field-effect capacitors, each having a first and second contact, each having a different flat-band voltage characteristic from the other and each having capacitance variable in response to a voltage applied to the first and second contacts; means coupled to the first and second field-effect capacitors for producing substantially identical capacitance in the first and second field-effect capacitors; and means for coupling to the first contacts of the first and second field-effect capacitors.
Claim 14
Dependent Claim
79 words
A voltage reference comprising: first and second field-effect capacitors, each having a first and second contact, each having a different flat-band voltage characteristic from the other and each having capacitance variable in response to a voltage applied to the first and second contacts; means coupled to the first and second field-effect capacitors for producing substantially identical capacitance in the first and second field-effect capacitors; and means for coupling to the first contacts of the first and second field-effect capacitors.
Claim 15
Dependent Claim
64 words
A voltage reference as in claim 12 wherein the first and second field-effect capacitors have substrates of substantially similar semiconductor material, the first capacitor has a first gate field plate of a first metal and the second capacitor has a second gate field plate of a second metal for producing different respective metal to semiconductor work-function differences in the first and second field-effect capacitors.
Claim 16
Dependent Claim
82 words
A voltage reference as in claim 12 wherein the first and second field-effect capacitors have substrates of a first semiconductor material, a gate field plate of the first capacitor is of a second semiconductor material and a gate field plate of the second capacitor is of a third semicoductor material, the first and second semiconductor materials in combination producing a semiconductor to semiconductor work-function difference which is different from the semiconductor to semiconductor work-function difference of the first and third semiconductor materials.
Claim 17
Dependent Claim
47 words
A voltage reference as in claim 12 wherein the first and second field-effect capacitors have similar semiconductor substrates, the first field-effect capacitor has a gate field plate made of semiconductor material and the second field-effect capacitor has a gate field plate made of material including a metal.
Claim 18
Dependent Claim
29 words
A voltage reference as in claim 12 wherein the first field-effect capacitor has a first interface state density and the second field-effect capacitor has a second interface state density.
Claim 19
Dependent Claim
47 words
A voltage reference as in claim 12 wherein the first field-effect capacitor has a first fixed charge per unit area located at its semiconductor to insulator interface and the second field-effect capacitor has a second fixed charge per unit area located at its semiconductor to insulator interface.
Claim 20
Dependent Claim
33 words
A voltage reference as in claim 12 wherein the first field-effect capacitor has an insulator with a first charge distribution and the second field-effect capacitor has an insulator with a second charge distribution.
Claim 21
Dependent Claim
67 words
A voltage reference as in claim 12 wherein the first field-effect capacitor has multiple insulators, the insulator contacting the semiconductor of the first field-effect capacitor being sufficiently thin to permit tunneling; and bias means coupled to the gate contact of the first field-effect capacitor for tunneling charge into the first field-effect capacitor and producing a difference between flat-band voltage characteristics of the first and second field-effect capacitors.
Claim 22
Dependent Claim
31 words
A voltage reference as in claim 19 wherein the second field-effect capacitor has multiple insulators, the insulator contacting the semiconductor of the second field-effect capacitor being sufficiently thin to permit tunneling.
Claim 23
Dependent Claim
50 words
A voltage reference as in claim 19 wherein the first field-effect capacitor has a silicon substrate, a first insulator of silicon dioxide in contact with the silicon substrate and a second insulator of silicon nitride in contact with the first insulator and the gate contact of the first field-effect capacitor.
Claim 24
Dependent Claim
50 words
A voltage reference as in claim 21 wherein the second field-effect capacitor has a silicon substrate, a first insulator of silicon dioxide in contact with the silicon substrate and a second insulator of silicon nitride in contact with the first insulator and the gate contact of the second field-effect capacitor.
References Cited (Backward Citations)
US3673471A
Cited
US3806742A
Cited
US3870906A
Cited
US3875430A
Cited
US3868274A
Cited
US3868274B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-17 | 1980-02-16 | 1980-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-17 | 1984-02-16 | 1984-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-17 | 1988-02-16 | 1988-08-17 | $7700.00 | Window Closed / Lapsed |