US5491657A
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Method for bulk (or byte) charging and discharging an array of flash EEPROM memory cells
Assignee: Cypress Semiconductor Corp
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Filing: 1995-02-24
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Granted: 1996-02-13
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Expires: 2015-02-24
Abstract
Abstract There is provided an improved method for bulk (or byte) programming an array of flash EEPROM memory cells. A negative voltage is applied to the substrate of the array. A reference voltage of zero volts is applied simultaneously to the drain regions of selected memory cells that are to be programmed. There is also applied simultaneously the same reference voltage of zero volts to the control gates of the selected memory cells. The present invention provides for low current consumption and fast programming of the memory cell, which require only a single, low voltage power supply. The endurance reliability is greater than 100,000 cycles.
Inventors
- 👤 Sameer S. Haddad
- 👤 Hao Fang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:33
CPC Classifications
G; G11; G11C; G11C16/00; G11C16/02; G11C16/06; G11C16/34; G11C16/3436; G11C16/3468; G11C16/3477; G11C16/10; G11C16/14; G11C16/16; G11C16/3418; G11C16/3427; G11C16/3486; G11C2216/00; G11C2216/12; G11C2216/16; G11C2216/18
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
162 words
A method for bulk (or byte) charging an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes a common source line extending along at least one of the rows, common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a negative voltage to the substrate of the array; applying simultaneously a reference voltage of zero volts to drain regions of selected memory cells in the array that are to be programmed; and applying simultaneously the same reference voltage of zero volts to control gates of the selected memory cells, said source regions being allowed to float.
Claim 2
Independent Claim
162 words
A method for bulk (or byte) charging an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes a common source line extending along at least one of the rows, common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a negative voltage to the substrate of the array; applying simultaneously a reference voltage of zero volts to drain regions of selected memory cells in the array that are to be programmed; and applying simultaneously the same reference voltage of zero volts to control gates of the selected memory cells, said source regions being allowed to float.
Claim 3
Dependent Claim
21 words
A method as claimed in claim 1, wherein said negative voltage is in the range of -6.0 V to -10 V.
Claim 4
Dependent Claim
15 words
A method as claimed in claim 2, wherein said negative voltage is approximately -8.5 V.
Claim 5
Dependent Claim
18 words
A method as claimed in claim 3, wherein said negative voltage is applied for less than 100 mS.
Claim 6
Dependent Claim
32 words
A method as claimed in claim 1, further including step of applying a current-limiting device in series with the drain regions so as to clamp drain current during programming and erase operations.
Claim 7
Dependent Claim
55 words
A method as claimed in claim 1, further including step of applying a programming-inhibiting voltage of a polarity and magnitude the same as voltage on the substrate to the control gates of non-selected memory cells in the array which are not to be programmed during said programming operation so as to insure against a disturbance.
Claim 8
Dependent Claim
31 words
A method as claimed in claim 6, further including step of applying a second negative voltage to drain regions of the non-selected memory cells so as to insure against a disturbance.
Claim 9
Dependent Claim
29 words
A method as claimed in claim 7, wherein said second negative voltage is approximately -3 V so as to reduce the field below breakdown and thus eliminate any disturbance.
Claim 10
Dependent Claim
18 words
A method as claimed in claim 1, wherein said source regions are allowed to float during flash programming.
Claim 11
Independent Claim
207 words
A method for bulk (or byte) charging and source-side erasing an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes a common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a first negative voltage to the substrate of the array; applying simultaneously a reference voltage of zero volts to drain regions of selected memory cells in the array that are to be programmed; applying simultaneously the same reference voltage of zero volts to control gates of the selected memory cells; said method further including the source-side erasing steps of applying zero volts to the substrate of the array; applying a positive voltage to the source regions of the array; and applying a second negative voltage to the control gates, said drain regions being allowed to float during erasure.
Claim 12
Independent Claim
207 words
A method for bulk (or byte) charging and source-side erasing an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes a common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a first negative voltage to the substrate of the array; applying simultaneously a reference voltage of zero volts to drain regions of selected memory cells in the array that are to be programmed; applying simultaneously the same reference voltage of zero volts to control gates of the selected memory cells; said method further including the source-side erasing steps of applying zero volts to the substrate of the array; applying a positive voltage to the source regions of the array; and applying a second negative voltage to the control gates, said drain regions being allowed to float during erasure.
Claim 13
Dependent Claim
22 words
A method as claimed in claim 10; wherein said first negative voltage is in the range of -6.0 V to -10 V.
Claim 14
Dependent Claim
16 words
A method as claimed in claim 11, wherein said first negative voltage is approximately -8.5 V.
Claim 15
Dependent Claim
19 words
A method as claimed in claim 12, wherein said first negative voltage is applied for less than 10 μS.
Claim 16
Dependent Claim
32 words
A method as claimed in claim 13, further including step of applying a current-limiting device in series with the drain regions so as to clamp drain current during programming and erase operations.
Claim 17
Dependent Claim
54 words
A method as claimed in claim 10, further includes step of applying a programming-inhibiting voltage of a polarity and magnitude the same as voltage on the substrate to control gates of non-selected memory cells in the array which are not to be programmed during said programming operation so as to insure against a disturbance.
Claim 18
Dependent Claim
31 words
A method as claimed in claim 15, further including step of applying a third negative voltage to drain regions of the non-selected memory cells so as to insure against a disturbance.
Claim 19
Dependent Claim
29 words
A method as claimed in claim 16, wherein said third negative voltage is approximately -3 V so as to reduce the field below breakdown and thus eliminate any disturbance.
Claim 20
Dependent Claim
18 words
A method as claimed in claim 10, wherein said source regions are allowed to float during flash programming.
Claim 21
Independent Claim
224 words
A method for bulk (or byte) charging and flash erasing an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes a common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a negative voltage to the substrate of the array; applying simultaneously a reference voltage of zero volts to drain regions of selected memory cells in the array that are to be programmed; applying simultaneously the same reference voltage of zero volts to control gates of the selected memory cells; said method further including the flash erasing steps of applying a positive voltage the same magnitude as voltage on said substrate during flash programming to the drain regions of the array; and applying the zero volts the same as that of said drain region during flash programming operations to the control gate and substrates of the array, said source regions being allowed to float during erasure.
Claim 22
Independent Claim
224 words
A method for bulk (or byte) charging and flash erasing an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes a common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a negative voltage to the substrate of the array; applying simultaneously a reference voltage of zero volts to drain regions of selected memory cells in the array that are to be programmed; applying simultaneously the same reference voltage of zero volts to control gates of the selected memory cells; said method further including the flash erasing steps of applying a positive voltage the same magnitude as voltage on said substrate during flash programming to the drain regions of the array; and applying the zero volts the same as that of said drain region during flash programming operations to the control gate and substrates of the array, said source regions being allowed to float during erasure.
Claim 23
Dependent Claim
56 words
A method as claimed in claim 19, further includes step of applying a programming-inhibiting voltage of a polarity and magnitude the same as voltage on the substrate to the control gates of non-selected memory cells in the array which are not to be programmed during said flash programming operations so as to insure against a disturbance.
Claim 24
Independent Claim
159 words
A method for bulk (or byte) charging an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a reference voltage of zero volts to the substrate of the array; applying simultaneously a positive voltage to drain regions of selected memory cells in the array that are to be programmed; and applying simultaneously the same positive voltage to control gates of the selected memory cells, said source regions being allowed to float.
Claim 25
Independent Claim
159 words
A method for bulk (or byte) charging an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a reference voltage of zero volts to the substrate of the array; applying simultaneously a positive voltage to drain regions of selected memory cells in the array that are to be programmed; and applying simultaneously the same positive voltage to control gates of the selected memory cells, said source regions being allowed to float.
Claim 26
Independent Claim
159 words
A method for bulk (or byte) charging an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a reference voltage of zero volts to the substrate of the array; applying simultaneously a positive voltage to source regions of selected memory cells in the array that are to be programmed; and applying simultaneously the same positive voltage to control gates of the selected memory cells, said drain regions being allowed to float.
Claim 27
Independent Claim
159 words
A method for bulk (or byte) charging an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) charging steps of: applying a reference voltage of zero volts to the substrate of the array; applying simultaneously a positive voltage to source regions of selected memory cells in the array that are to be programmed; and applying simultaneously the same positive voltage to control gates of the selected memory cells, said drain regions being allowed to float.
Claim 28
Independent Claim
161 words
A method for bulk (or byte) discharging an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes a common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) discharging steps of: applying a low negative voltage to the substrate of the array; applying simultaneously an intermediate positive voltage to drain regions of selected memory cells in the array that are to be erased; and applying simultaneously a reference voltage of zero volts to control gates of the selected memory cells, said source regions being allowed to float.
Claim 29
Independent Claim
161 words
A method for bulk (or byte) discharging an array of flash EEPROM memory cells, said memory cells being formed on a substrate to define columns and rows, where the substrate includes a common source line extending along at least one of the rows, a common substrate line, and a plurality of bit lines extending along respective columns, where each memory cell includes an n-type source region coupled to the common source line, a control gate, a floating gate, a channel region, and an n-type drain region coupled to a respective one of the bit lines, said method comprising the bulk (or byte) discharging steps of: applying a low negative voltage to the substrate of the array; applying simultaneously an intermediate positive voltage to drain regions of selected memory cells in the array that are to be erased; and applying simultaneously a reference voltage of zero volts to control gates of the selected memory cells, said source regions being allowed to float.
References Cited (Backward Citations)
US4451905A
Cited
US5084843A
Cited
US5021999A
Cited
US5077691A
Cited
US5349553A
Cited
US5357463A
Cited
US5349220A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1999-02-12 | 1999-08-14 | 2000-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-12 | 2003-08-14 | 2004-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-12 | 2007-08-14 | 2008-02-13 | $7700.00 | Window Closed / Lapsed |