US6060723A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controllable conduction device
Assignee: Hitachi Ltd
•
Filing: 1998-06-10
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Granted: 2000-05-09
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Expires: 2018-06-10
Abstract
Abstract A controllable conduction device in the form of a transistor comprises source and drain regions 5, 2 between which extends a conduction path P for charge carriers, a gate 4 for controlling charge carrier flow along the conduction path and a multiple layer structure 3 providing a multiple tunnel junction configuration in the conduction path, with the result that current leakage is blocked by the multiple tunnel junction configuration when the transistor is in its off state. Vertical and lateral transistor configurations are described, together with use of the transistor in complimentary pairs and for a random access memory cell. Improved gate structures are described which are also applicable to memory devices that incorporate the tunnel barrier configuration to store charge on the memory node.
Inventors
- 👤 Kazuo Nakazato
- 👤 Kiyoo Itoh
- 👤 Hiroshi Mizuta
- 👤 Toshikazu Shimada
- 👤 Hideo Sunami
- 👤 Tatsuya Teshima
- 👤 Toshiyuki Mine
- 👤 Ken Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:30
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/036; B; B82; B82Y; B82Y10/00; H10B10/00; H10B12/05; H10B12/053; H10B12/30; H10B12/31; H10B12/33; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0411; H10D30/60; H10D30/67; H10D30/6704; H10D30/6706; H10D30/6713; H10D30/6728; H10D30/674; H10D30/6741; H10D30/6748; H10D30/68; H10D30/681; H10D30/6891; H10D62/00; H10D62/80; H10D62/81; H10D62/815; H10D62/8161; H10D62/8162; H10D62/8163; H10D64/00; H10D64/01; H10D64/031; H10D64/035; H10D8/00; H10D8/70; H10D8/755
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
120 words
A controllable conduction device comprising: source and drain regions, a conduction path for charge carriers between the source and drain regions, a gate for controlling charge carrier flow along the conduction path, and a barrier structure in the conduction path formed of regions of relatively conductive and non-conductive material such that under a first bias condition charge carrier flow can occur along the path and under a second bias condition the regions present a tunnel barrier configuration that inhibits charge carrier flow along the path, the regions providing an energy band profile that comprises a dimensionally relatively wide barrier component with a relatively low barrier height, and at least one relatively narrow barrier component with a relatively high barrier height.
Claim 2
Dependent Claim
120 words
A controllable conduction device comprising: source and drain regions, a conduction path for charge carriers between the source and drain regions, a gate for controlling charge carrier flow along the conduction path, and a barrier structure in the conduction path formed of regions of relatively conductive and non-conductive material such that under a first bias condition charge carrier flow can occur along the path and under a second bias condition the regions present a tunnel barrier configuration that inhibits charge carrier flow along the path, the regions providing an energy band profile that comprises a dimensionally relatively wide barrier component with a relatively low barrier height, and at least one relatively narrow barrier component with a relatively high barrier height.
Claim 3
Dependent Claim
22 words
A device according to claim 1 wherein the regions comprise a plurality of alternating layers of relatively conductive and non conductive material.
Claim 4
Dependent Claim
12 words
A device according to claim 2 wherein the alternating layers contain silicon.
Claim 5
Dependent Claim
14 words
A device according to claim 3 comprising alternating layers of silicon and silicon nitride.
Claim 6
Dependent Claim
16 words
A device according to claim 3 comprising alternating layers of silicon and an oxide of silicon.
Claim 7
Dependent Claim
21 words
A device according to claim 2 wherein at least one of the layers has a thickness of 5 nm or less.
Claim 8
Dependent Claim
22 words
A device according to claim 2 wherein at least one of the non-conductive layers has a thickness of 3 nm or less.
Claim 9
Dependent Claim
20 words
A device according to claim 2 wherein at least one of the source and drain regions overlies the layer configuration.
Claim 10
Dependent Claim
17 words
A device according to claim 8 wherein the other of the regions underlies the multiple layer configuration.
Claim 11
Dependent Claim
19 words
A device according to claim 8 wherein both of the source and drain regions overlie the multiple layer configuration.
Claim 12
Dependent Claim
21 words
A device according to claim 10 wherein the gate extends into the multiple layer structure between the source and drain regions.
Claim 13
Dependent Claim
21 words
A device according to claim 1 including a substrate on which the layers of the multiple tunnel junction configuration are formed.
Claim 14
Dependent Claim
16 words
A device according to claim 12 wherein the substrate is formed of an electrically insulating material.
Claim 15
Dependent Claim
18 words
A device according to claim 13 wherein the substrate is formed of a quartz or a ceramic material.
Claim 16
Dependent Claim
14 words
A device according to claim 12 wherein the substrate is formed of a metal.
Claim 17
Dependent Claim
19 words
A device according to claim 12 wherein the substrate is formed of silicon with a layer of oxide thereon.
Claim 18
Dependent Claim
20 words
A transistor structure including a first and a second device each according to claim 1 and of different conductivity types.
Claim 19
Dependent Claim
15 words
A structure according to claim 17 wherein the devices are stacked one upon the other.
Claim 20
Dependent Claim
22 words
A memory cell including a charge storage capacitor and a device according to claim 1 for selectively writing charge to the capacitor.
Claim 21
Dependent Claim
9 words
An array of memory cells according to claim 19.
Claim 22
Independent Claim
142 words
A method of fabricating a controllable conduction device comprising: forming a multiple layer structure to provide a multiple tunnel junction configuration, and forming source and drain regions for a conduction path for charge carriers, forming a gate for controlling charge carrier flow along the conduction path, and forming a barrier structure in the conduction path that comprises regions of relatively conductive and non-conductive material such that under a first bias condition charge carrier flow can occur along the path and under a second bias condition the regions present a tunnel barrier configuration that inhibits charge carrier flow along the path, the regions in the absence of an applied bias presenting an energy band profile that comprises a dimensionally relatively wide barrier component with a relatively low barrier height, and at least one relatively narrow barrier component with a relatively high barrier height.
Claim 23
Independent Claim
142 words
A method of fabricating a controllable conduction device comprising: forming a multiple layer structure to provide a multiple tunnel junction configuration, and forming source and drain regions for a conduction path for charge carriers, forming a gate for controlling charge carrier flow along the conduction path, and forming a barrier structure in the conduction path that comprises regions of relatively conductive and non-conductive material such that under a first bias condition charge carrier flow can occur along the path and under a second bias condition the regions present a tunnel barrier configuration that inhibits charge carrier flow along the path, the regions in the absence of an applied bias presenting an energy band profile that comprises a dimensionally relatively wide barrier component with a relatively low barrier height, and at least one relatively narrow barrier component with a relatively high barrier height.
Claim 24
Dependent Claim
19 words
A method according to claim 21 including forming the source and drain regions to be in an overlying relationship.
Claim 25
Dependent Claim
58 words
A method according to claim 21 including forming a first conductive doped layer on a substrate, forming the barrier structure as a multiple layer structure to overlie the first conductive doped layer, forming a second doped conductive layer to overlie the multiple layer structure, and configuring the first and second doped layers into the source and drain regions.
Claim 26
Dependent Claim
20 words
A method according to claim 21 including forming the source and drain regions to be in a laterally spaced relationship.
Claim 27
Dependent Claim
14 words
A method according to claim 21 including forming the barrier structure by modulation doping.
Claim 28
Dependent Claim
12 words
A controllable conduction device fabricated by a method according to claim 21.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-05-09 | 2003-11-08 | 2004-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-05-09 | 2007-11-08 | 2008-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-05-09 | 2011-11-08 | 2012-05-09 | $7700.00 | Window Closed / Lapsed |