Semiconductor memory device
First Claim
1. A method for controlling a semiconductor memory device that comprises:
- a memory block including a plurality of memory strings, the plurality of memory strings including a first memory string and a second memory string,the first memory string includinga first transistor,a second transistor, anda plurality of first memory cells,the second memory string includinga third transistor,a fourth transistor, anda plurality of second memory cells;
a first bit line connected to a node of the first transistor and a node of the third transistor;
a first select gate line connected to a gate of the first transistor;
a second select gate line connected to a gate of the third transistor;
a source line connected to a node of the second transistor and a node of the fourth transistor; and
a plurality of word lines, each of the word lines connected to one of gates of the first memory cells and one of gates of the second memory cells, said method comprising;
performing an erase verify operation on the memory block, wherein the erase verify operation includes;
applying a first selection voltage to the first select gate line at a first time;
while applying the first selection voltage to the first select gate line, applying an erase verify voltage to the plurality of word lines; and
applying a second selection voltage to the second select gate line at a second time after the first time without making the voltage applied to the plurality of word lines zero voltage at any time between the first time and the second time.
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Accused Products
Abstract
A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
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Citations
20 Claims
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1. A method for controlling a semiconductor memory device that comprises:
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a memory block including a plurality of memory strings, the plurality of memory strings including a first memory string and a second memory string, the first memory string including a first transistor, a second transistor, and a plurality of first memory cells, the second memory string including a third transistor, a fourth transistor, and a plurality of second memory cells; a first bit line connected to a node of the first transistor and a node of the third transistor; a first select gate line connected to a gate of the first transistor; a second select gate line connected to a gate of the third transistor; a source line connected to a node of the second transistor and a node of the fourth transistor; and a plurality of word lines, each of the word lines connected to one of gates of the first memory cells and one of gates of the second memory cells, said method comprising; performing an erase verify operation on the memory block, wherein the erase verify operation includes; applying a first selection voltage to the first select gate line at a first time; while applying the first selection voltage to the first select gate line, applying an erase verify voltage to the plurality of word lines; and applying a second selection voltage to the second select gate line at a second time after the first time without making the voltage applied to the plurality of word lines zero voltage at any time between the first time and the second time. - View Dependent Claims (2, 3, 4, 5)
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6. A method for controlling a semiconductor memory device that comprises:
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a plurality of memory strings including a first memory string and a second memory string, each of the memory strings including a first transistor, a second transistor, and a plurality of memory cells serially connected between the first transistor and the second transistor, a first bit line connected to nodes of the first transistors in the first memory string and the second memory string; a first select gate line connected to a gate of the first transistor of the first memory string; a second select gate line connected to a gate of the first transistor of the second memory string; and a plurality of word lines connected to at least gates of memory cells of the first memory string and the second memory string, said method comprising; performing an erase verify operation on the plurality of memory strings, wherein the erase verify operation includes; applying a first selection voltage to the first select gate line at a first time; while applying the first selection voltage to the first select gate line, applying an erase verify voltage to the plurality of word lines; and applying a second selection voltage to the second select gate line at a second time after the first time without making the voltage applied to the plurality of word lines zero voltage at any time between the first time and the second time. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method for controlling a semiconductor memory device that comprises:
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a memory block including a plurality of memory strings, the plurality of memory strings including a first memory string and a second memory string, the first memory string including a first transistor, a second transistor, and a plurality of first memory cells, the second memory string including a third transistor, a fourth transistor, and a plurality of second memory cells; a first bit line connected to a node of the first transistor and a node of the third transistor; a first select gate line connected to a gate of the first transistor; a second select gate line connected to a gate of the third transistor; a source line connected to a node of the second transistor and a node of the fourth transistor; and a plurality of word lines, each of the word lines connected to one of gates of the first memory cells and one of gates of the second memory cells, said method comprising; performing an erase verify operation on the memory block, wherein the erase verify operation includes; applying a first selection voltage to the first select gate line at a first time; while applying the first selection voltage to the first select gate line, applying an erase verify voltage to the plurality of word lines; and applying a second selection voltage to the second select gate line at a second time after the first time while keeping constant the voltage applied to the plurality of word lines between the first time and the second time. - View Dependent Claims (13, 14, 15, 16)
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17. A method for controlling a semiconductor memory device that comprises:
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a memory block including a plurality of memory strings, each of the memory strings being coupled to a different select gate line, the memory strings being coupled to a common bit line, the memory block being a unit of an erase verify operation, said method comprising performing the erase verify operation on the memory block, wherein the erase verify operation includes; selecting one of the memory strings at a first time; while selecting the one of the memory strings, applying an erase verify voltage to the memory strings; and selecting another one of the memory strings at a second time after the first time while keeping constant the voltage applied to the memory strings between the first time and the second time. - View Dependent Claims (18, 19, 20)
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Specification