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US5875129A Expired / Lapsed US ⏱️ 0.0 years remaining

Nonvolatile semiconductor memory device including potential generating circuit

Assignee: Toshiba Corp
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Filing: 1996-11-06
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Granted: 1999-02-23
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Expires: 2016-11-06
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Abstract

Abstract In a flash memory EEPROM, a memory cell MC is formed in a P-type semiconductor substrate. A peripheral transistor TR is formed in an N-type well. Another peripheral transistor TR is formed in a P-type well. The P-type well is by turn formed an N-type well and electrically insulated from the substrate. The substrate is typically provided with a metal back structure and its substrate voltage is set to predetermined voltages respectively for data erasure, data storage and data retrieval. With such an arrangement, the level of voltage stress with which the device is loaded during data erasure can be remarkably reduced to allow a down-sizing and an enhanced quality to be realized for the device.

Inventors

  • 👤 Shigeru Atsumi
  • 👤 Sumio Tanaka

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 20:28
CPC Classifications
H; H10; H10B; H10B69/00; G; G11; G11C; G11C16/00; G11C16/02; G11C16/06; G11C16/30; G11C16/08; H10B41/00; H10B41/40; H10B41/42; H10B41/49

Claims Analysis

Total Claims: 21
Claim 1
Independent Claim 86 words
A nonvolatile semiconductor memory device comprising: a semiconductor substrate having a P-conductivity type region; a P-channel transistor connected between a first terminal supplied with a first potential and said P-conductivity type region; first N-channel transistor connected between a second terminal supplied with a second potential and said P-conductivity type region; stacked gate memory cells formed on said P-conductivity type region; and a second N-channel transistor formed on said substrate, said second N-channel transistor being electrically separated from said P-conductivity type region by a double well structure.
Claim 2
Dependent Claim 86 words
A nonvolatile semiconductor memory device comprising: a semiconductor substrate having a P-conductivity type region; a P-channel transistor connected between a first terminal supplied with a first potential and said P-conductivity type region; first N-channel transistor connected between a second terminal supplied with a second potential and said P-conductivity type region; stacked gate memory cells formed on said P-conductivity type region; and a second N-channel transistor formed on said substrate, said second N-channel transistor being electrically separated from said P-conductivity type region by a double well structure.
Claim 3
Dependent Claim 39 words
A nonvolatile semiconductor memory device according to claim 1, wherein said first potential is a positive power supply potential which is the same as a potential supplied to drains of said stacked gate memory cells during a write operation.
Claim 4
Dependent Claim 39 words
A nonvolatile semiconductor memory device according to claim 1, wherein said first potential is a positive power supply potential which is the same as a potential supplied to gates of said stacked gate memory cells during a write operation.
Claim 5
Dependent Claim 38 words
A nonvolatile semiconductor memory device according to claim 1, wherein a back gate of said P-channel transistor is connected to said first terminal and a back gate of said first N-channel transistor is connected to said second terminal.
Claim 6
Dependent Claim 16 words
A nonvolatile semiconductor memory device according to claim 1, wherein said second potential is ground potential.
Claim 7
Dependent Claim 26 words
A nonvolatile semiconductor memory device according to claim 1, wherein said P-channel transistor is formed in an N-conductivity type well formed in said P-condutivity type region.
Claim 8
Dependent Claim 33 words
A nonvolatile semiconductor memory device according to claim 1, wherein said first N-channel transistor is formed on said semiconductor substrate and electrically separated from said P-conductivity type region by a double well structure.
Claim 9
Dependent Claim 56 words
A nonvolatile semiconductor memory device according to claim 1, further comprising a metal layer formed on a surface area of said semiconductor substrate, which is opposite to a surface area in which said P-conductivity type region, said P-condcutivity type transistor, said first N-channel transistor, said stacked gate memory cells, and said second N-channel transistor are formed.
Claim 10
Dependent Claim 133 words
A nonvolatile semiconductor memory device comprising: a semiconductor substrate having a region of a first conductivity type; a first transitor having a channel of the first conductivity type, said first transistor connected between a first terminal supplied with a first potential and siad region of the first conductivity type; a second transistor having a channel of a second conductivity type, said second transistor connected between a second terminal supplied with a second potential and siad region of the first conductivity type; nonvolatile memory cells formed on said region of the first conductivity type; and a third transistor having a channel of the second conductivity type, said third transistor formed on said semiconductor substrate and said third transistor being electrically separated from said region of the frist conductivity type by a double well structure.
Claim 11
Dependent Claim 133 words
A nonvolatile semiconductor memory device comprising: a semiconductor substrate having a region of a first conductivity type; a first transitor having a channel of the first conductivity type, said first transistor connected between a first terminal supplied with a first potential and siad region of the first conductivity type; a second transistor having a channel of a second conductivity type, said second transistor connected between a second terminal supplied with a second potential and siad region of the first conductivity type; nonvolatile memory cells formed on said region of the first conductivity type; and a third transistor having a channel of the second conductivity type, said third transistor formed on said semiconductor substrate and said third transistor being electrically separated from said region of the frist conductivity type by a double well structure.
Claim 12
Dependent Claim 38 words
A nonvolatile semiconductor memory device according to claim 9, wherein said first potential is a positive power supply potential which is the same as a potential supplied to drains of said nonvolatile memory cells during a write operation.
Claim 13
Dependent Claim 38 words
A nonvolatile semiconducutor memory device according to claim 9, wherein said first potential is a positive power supply potential which is the same as a potential supplied to gates of said nonvolatile memory cells during a write operation.
Claim 14
Dependent Claim 37 words
A nonvolatile semiconductor memory device according to claim 9, wherein a back gate of said first transistor is connected to said first terminal and a back gate of said second transistor is connected to said second terminal.
Claim 15
Dependent Claim 16 words
A nonvolatile semicondcutor memory device according to claim 9, wherin said second potential is ground potential.
Claim 16
Dependent Claim 32 words
A nonvolatile semiconductor memory device according to claim 9, wherein said first transistor is formed in a well of the second conductivity type formed in said region of the first conductivity type.
Claim 17
Dependent Claim 36 words
A nonvolatile semiconductor memory device according to claim 9, wherein said second transistor is formed on said semiconductor substrate and is electrically separated from said region of the first conductivity type by a double well structure.
Claim 18
Dependent Claim 56 words
A nonvolatile semiconductor memory device according to claim 9, further comprising a metal layer formed on a surface area of said semiconductor substrate, which is opposite to a surface area in which said region of the first conductivity type, said first transistor, said second transistor, said stacked gate memory cells, and said third transistor are formed.
Claim 19
Dependent Claim 19 words
A nonvolatile semiconductor memory device according to claim 9, wherein said nonvolatile memory cells are stacked gate memory cells.
Claim 20
Dependent Claim 171 words
A nonvolatile semiconductor memory device, comprising: a semiconductor substrate having a region of a first conductivity type; nonvolatile memory cells formed on said region of the first conductivity type; a first transitior for a peripheral circuit of said nonvolatile semiconductor memory device having a channel of a second conductivity type, said first transistor being electrically separated form said region of the first conductivity type by a double well structure; and a potential generating circuit for generating a potential applied to said region of the first conductivity type, said potential generating circuit comprising: a second transistor having a channel of the first conductivity type, a first end connected to a first potential, a second end connected to said region of the first conductivity type, and a gate supplied with an erase signal; and a third transistor having a channel of the second conductivity type, a first end connected to a second potential, a second end connected to said region of the first conductivity type and a gate supplied with the erase signal.
Claim 21
Dependent Claim 171 words
A nonvolatile semiconductor memory device, comprising: a semiconductor substrate having a region of a first conductivity type; nonvolatile memory cells formed on said region of the first conductivity type; a first transitior for a peripheral circuit of said nonvolatile semiconductor memory device having a channel of a second conductivity type, said first transistor being electrically separated form said region of the first conductivity type by a double well structure; and a potential generating circuit for generating a potential applied to said region of the first conductivity type, said potential generating circuit comprising: a second transistor having a channel of the first conductivity type, a first end connected to a first potential, a second end connected to said region of the first conductivity type, and a gate supplied with an erase signal; and a third transistor having a channel of the second conductivity type, a first end connected to a second potential, a second end connected to said region of the first conductivity type and a gate supplied with the erase signal.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2002-02-22 2002-08-24 2003-02-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2006-02-22 2006-08-24 2007-02-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2010-02-22 2010-08-24 2011-02-23 $7700.00 Window Closed / Lapsed

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