US4841346A
Expired / Lapsed
US
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Field-effect transistor devices
Assignee: Toshiba Corp
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Filing: 1987-03-20
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Granted: 1989-06-20
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Expires: 2007-03-20
Abstract
Abstract A MOSFET utilizes a buried channel structure comprising a buried channel between a source electrode and a drain electrode. The device also comprises a gate electrode made of material whose Fermi level is located between a conduction band and a valency band of a semiconductor. An impurity concentration in the substrate is relatively high because of buried channel structure.
Inventors
- 👤 Tatsuo Noguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:07
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/637; H10D64/00; H10D64/60; H10D64/66; H10D64/665; H10D64/667; H10D64/668
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
104 words
In an insulated gate semiconductor device comprising a semiconductor substrate having a first conductivity, a source electrode and a drain electrode having a second conductivity and formed on the substrate, a buried channel having said first conductivity and formed between the source electrode and the drain electrode, and a gate electrode formed above the channel through the intermediary of an insulation layer, the improvement wherein said gate electrode is made of material having a Fermi level located between a conduction band and a valence band of the semiconductor, and wherein the substrate has an impurity concentration of more than 1×10 17 cm -3 .
Claim 2
Dependent Claim
104 words
In an insulated gate semiconductor device comprising a semiconductor substrate having a first conductivity, a source electrode and a drain electrode having a second conductivity and formed on the substrate, a buried channel having said first conductivity and formed between the source electrode and the drain electrode, and a gate electrode formed above the channel through the intermediary of an insulation layer, the improvement wherein said gate electrode is made of material having a Fermi level located between a conduction band and a valence band of the semiconductor, and wherein the substrate has an impurity concentration of more than 1×10 17 cm -3 .
Claim 3
Dependent Claim
19 words
A semi-conductor device according to claim 1, wherein the gate electrode is made of tungsten, molybdenum or silicides thereof.
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) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |