US5548150A
Expired / Lapsed
US
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Field effect transistor
Assignee: Toshiba Corp
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Filing: 1995-04-17
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Granted: 1996-08-20
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Expires: 2015-04-17
Abstract
Abstract A high-resistant p-silicon layer is formed on a silicon substrate through a silicon oxide film. N-source and n-drain layers are selectively formed in the surface of the high-resistant p-silicon layer. A gate electrode is formed through a gate insulating film on a channel region between the source and drain layers. To induce an n-inverted layer under the gate electrode, a p-base layer is formed in the high-resistant p-silicon layer. A depletion layer extending from a pn junction between the n-drain layer and the high-resistant p-silicon layer reaches the silicon oxide film in a thermal equilibrium state. Part of the high-resistant p-silicon layer extends into a channel region between the drain and base layers. The drain and base layers are connected to each other through part of the depletion layer in the thermal equilibrium state. A field effect transistor having a high-speed operation is provided.
Inventors
- 👤 Ichiro Omura
- 👤 Akio Nakagawa
- 👤 Tadashi Sakai
- 👤 Masayuki Sekimura
- 👤 Hideyuki Funaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:20
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/64; H10D30/65; H10D30/657; H01; H01F; H01F41/00; H01F41/02; H01F41/04; H01F41/041; H01F41/046; H10D12/00; H10D12/411; H10D18/00; H10D18/251; H10D30/01; H10D30/021; H10D30/031; H10D30/0321; H10D30/0323; H10D30/601; H10D30/603; H10D30/66; H10D30/668; H10D30/67; H10D30/6704; H10D30/6708; H10D30/6713; H10D30/6715; H10D30/6717; H10D30/6727; H10D62/00; H10D62/10; H10D62/13; H10D62/149; H10D62/151; H10D62/156; H10D62/157; H10D62/17; H10D62/213; H10D62/221; H10D62/235; H10D62/299; H10D62/307; H10D62/351; H10D62/357; H10D62/364; H10D62/378; H10D64/00; H10D64/111; H10D64/20; H10D64/27; H10D64/529; H10D86/00; H10D86/201; H10D89/00; H10D89/60; H10D89/601; H10D89/611; H01F17/00; H01F17/0006; H01F2017/0086; H10D62/117; H10D62/124; H10D62/126; H10D64/311; H10D64/411; H10D64/511; H10D64/514; H10D64/516; Y; Y10; Y10S; Y10S257/00; Y10S257/901
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
235 words
A high-frequency MOS field effect transistor comprising: a substrate comprising a first layer of an insulator material and a second layer of a semiconductor material; an active layer of said semiconductor material formed on a surface of said first layer; a source layer of a first conductivity type formed on a surface of said active layer and extending to said first layer; a source electrode connected to said source layer; a drain layer of the first conductivity type formed in said active layer and extending from said active layer surface to said first layer and not in contact with said source layer; a drain electrode connected to said drain layer; a base layer of a second conductivity type formed in said active layer extending from said surface of said active layer to said first layer so as to induce an inverted layer of the first conductivity type between said source and drain layers; a gate insulating film formed on said base layer; a gate electrode formed on a surface of said gate insulating film over said base layer; a short-circuiting layer formed in said active layer surface adjacent to said source layer to interconnect said base layer and said source electrode; a connecting member of an electrically and thermally conductive material extending through said first layer to electrically and thermally connect said source electrode to said second layer; and means for grounding said second layer.
Claim 2
Dependent Claim
235 words
A high-frequency MOS field effect transistor comprising: a substrate comprising a first layer of an insulator material and a second layer of a semiconductor material; an active layer of said semiconductor material formed on a surface of said first layer; a source layer of a first conductivity type formed on a surface of said active layer and extending to said first layer; a source electrode connected to said source layer; a drain layer of the first conductivity type formed in said active layer and extending from said active layer surface to said first layer and not in contact with said source layer; a drain electrode connected to said drain layer; a base layer of a second conductivity type formed in said active layer extending from said surface of said active layer to said first layer so as to induce an inverted layer of the first conductivity type between said source and drain layers; a gate insulating film formed on said base layer; a gate electrode formed on a surface of said gate insulating film over said base layer; a short-circuiting layer formed in said active layer surface adjacent to said source layer to interconnect said base layer and said source electrode; a connecting member of an electrically and thermally conductive material extending through said first layer to electrically and thermally connect said source electrode to said second layer; and means for grounding said second layer.
Claim 3
Dependent Claim
23 words
The transistor according to claim 1, wherein said drain electrode has an extending portion opposite said source electrode with an insulating layer therebetween.
Claim 4
Dependent Claim
40 words
The transistor according to claim 1, wherein said source layer comprises a plurality of source layer portions and said short-circuiting layer comprises a plurality of short circuiting layer portions, said source layer portions and short-circuiting layer portions being alternately arranged.
Claim 5
Dependent Claim
29 words
The transistor according to claim 1, wherein said connecting member extends through a trench formed in said first layer, said trench being not completely filled with said connecting member.
Claim 6
Dependent Claim
234 words
A field effect transistor comprising: a substrate; an active layer arranged on said substrate and essentially consisting of a semiconductor material; first and second base layers of a second conductivity type formed in a surface of said active layer so as to be in contact with each other, said first base layer having an electrical resistance higher than that of said second base layer and being arranged on said substrate; a source layer of a first conductivity type formed in a surface of said second base layer; a source electrode connected to said source layer; a drain layer of the first conductivity type formed in a surface of said first base layer; a drain electrode connected to said drain layer; and a gate electrode facing said second base layer through a gate insulating film for inducing an inverted layer of the first conductivity type in said second base layer between said source and drain layers, wherein a depth, W, and an impurity concentration, N, of said first base layer between said drain layer and said substrate are such that a depletion layer formed in said first base layer extends from a junction between said drain and first base layers to said substrate in a thermal equilibrium state when a voltage, V, applied between said source and drain electrodes is zero volts and thus also in an operation state when said inverted layer is formed.
Claim 7
Dependent Claim
234 words
A field effect transistor comprising: a substrate; an active layer arranged on said substrate and essentially consisting of a semiconductor material; first and second base layers of a second conductivity type formed in a surface of said active layer so as to be in contact with each other, said first base layer having an electrical resistance higher than that of said second base layer and being arranged on said substrate; a source layer of a first conductivity type formed in a surface of said second base layer; a source electrode connected to said source layer; a drain layer of the first conductivity type formed in a surface of said first base layer; a drain electrode connected to said drain layer; and a gate electrode facing said second base layer through a gate insulating film for inducing an inverted layer of the first conductivity type in said second base layer between said source and drain layers, wherein a depth, W, and an impurity concentration, N, of said first base layer between said drain layer and said substrate are such that a depletion layer formed in said first base layer extends from a junction between said drain and first base layers to said substrate in a thermal equilibrium state when a voltage, V, applied between said source and drain electrodes is zero volts and thus also in an operation state when said inverted layer is formed.
Claim 8
Dependent Claim
64 words
The transistor according to claim 5, wherein said depth, W, and impurity concentration, N, are determined according to: W<{2ε(V.sub.bi -2kT/q+V)/(qN)}.sup.1/2, where ε is a dielectric constant of said active layer, q is an elementary electric charge, k is Boltzman's constant, V is said voltage applied between said source and drain electrodes, and V bi is a potential between said drain and first base layers.
Claim 9
Dependent Claim
39 words
The transistor according to claim 5, wherein said drain layer is arranged in a spaced relation with said second base layer, and said depletion layer extends from said drain layer to said second base layer in said operation state.
Claim 10
Dependent Claim
25 words
The transistor according to claim 7, wherein said depletion layer extends from said drain layer to said second base layer in said thermal equilibrium state.
Claim 11
Dependent Claim
15 words
The transistor according to claim 5, wherein said drain layer contacts said second base layer.
Claim 12
Dependent Claim
46 words
The transistor according to claim 5, wherein said substrate comprises a first layer essentially consisting of a material having a lower dielectric constant than that of said semiconductor material of said active layer, said first and second base layers being arranged on said first substrate layer.
Claim 13
Dependent Claim
23 words
The transistor according to claim 5, wherein said substrate comprises an insulative surface on which said first and second base layers are arranged.
Claim 14
Dependent Claim
36 words
The transistor according to claim 11, wherein said substrate comprises a first layer essentially consisting of an insulative material and a backside layer essentially consisting of a semiconductor material, said first layer having said insulative surface.
Claim 15
Dependent Claim
33 words
The transistor according to claim 12, further comprising a connecting member essentially consisting of a thermally conductive material extending through said first substrate layer into thermal connection with said active and backside layers.
Claim 16
Dependent Claim
36 words
The transistor according to claim 5, wherein said substrate comprises a first layer essentially consisting of a low-resistant semiconductor material of the second conductivity type, said first base layer being arranged on said first substrate layer.
Claim 17
Dependent Claim
228 words
A field effect transistor comprising: a substrate, an active layer arranged on said substrate and essentially consisting of silicon; first and second base layers of a second conductivity type formed in a surface of said active layer in contact with each other, said first base layer having an electrical resistance higher than that of said second base layer and arranged on said substrate; a source layer of a first conductivity type formed in a surface of said second base layer; a source electrode connected to said source layer; a drain layer of the first conductivity type formed in a surface of said first base layer; a drain electrode connected to said drain layer; and a gate electrode facing said second base layer through a gate insulating film for inducing an inverted layer of the first conductivity type in said second base layer between said source and drain layers, wherein a depth, W, and an impurity concentration, N, of said first base layer between said drain layer and said substrate are determined such that a depletion layer formed in said first base layer extends from a junction between said drain and first base layers to said substrate in a thermal equilibrium state when a voltage, V, applied between said source and drain electrodes is zero volts and thus also in an operation state when said inverted layer is formed.
Claim 18
Dependent Claim
228 words
A field effect transistor comprising: a substrate, an active layer arranged on said substrate and essentially consisting of silicon; first and second base layers of a second conductivity type formed in a surface of said active layer in contact with each other, said first base layer having an electrical resistance higher than that of said second base layer and arranged on said substrate; a source layer of a first conductivity type formed in a surface of said second base layer; a source electrode connected to said source layer; a drain layer of the first conductivity type formed in a surface of said first base layer; a drain electrode connected to said drain layer; and a gate electrode facing said second base layer through a gate insulating film for inducing an inverted layer of the first conductivity type in said second base layer between said source and drain layers, wherein a depth, W, and an impurity concentration, N, of said first base layer between said drain layer and said substrate are determined such that a depletion layer formed in said first base layer extends from a junction between said drain and first base layers to said substrate in a thermal equilibrium state when a voltage, V, applied between said source and drain electrodes is zero volts and thus also in an operation state when said inverted layer is formed.
Claim 19
Dependent Claim
54 words
The transistor according to claim 15, wherein said depth, W, and impurity concentration, N, are determined according to: W.sup.2 N/(0.8+V)<2ε/q, where ε is a dielectric constant of said active layer, q is an elementary electric charge, V is said voltage applied between said source and drain electrodes, and 2ε/q is about 1.25×10 7 .
Claim 20
Dependent Claim
38 words
The transistor according to claim 15, wherein said drain layer is arranged in spaced relation with said second base layer, and said depletion layer extends from said drain layer to said second base layer in said operation state.
Claim 21
Dependent Claim
25 words
The transistor according to claim 17, wherein said depletion layer extends from said drain layer to said second base layer in said thermal equilibrium state.
Claim 22
Dependent Claim
41 words
The transistor according to claim 15, wherein said substrate comprises a first layer essentially consisting of an insulative material and a backside layer essentially consisting of a semiconductor material, said first base layer being arranged on said first and second layers.
Claim 23
Dependent Claim
32 words
The transistor according to claim 19, further comprising a connecting member essentially consisting of a thermally conductive material extending through said first layer into thermal connection with said active and backside layers.
References Cited (Backward Citations)
US3673471A
Cited
US4042945A
Cited
JPS56150854A
Cited
JPS6118165A
Cited
US5241210A
Cited
US4982263A
Cited
US4922327A
Cited
JPH01238062A
Cited
JPH01238066A
Cited
US5068700A
Cited
JPH02214165A
Cited
US5160989A
Cited
US5241211A
Cited
US5113236A
Cited
US5315134A
Cited
US5329142A
Cited
US5276338A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-08-20 | 2000-02-19 | 2000-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-20 | 2004-02-19 | 2004-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-08-20 | 2008-02-19 | 2008-08-20 | $7700.00 | Window Closed / Lapsed |