Semiconductor memory device
First Claim
1. A semiconductor memory device, comprising:
- a plurality of word lines;
a plurality of bit lines;
a plurality of memory cells at intersections of the word lines and the bit lines;
a word line driver configured to apply a voltage to a selected word line among the plurality of word lines;
a sense amplifier circuit configured to detect the data of at least one of the memory cells; and
a controller configured to control the word line driver and the sense amplifier,wherein a write sequence for writing first data to a selected memory cell connected to the selected word line includes a write loop that includes a write operation in which a write voltage is applied to the selected word line by the word line driver, and a verify operation during which, when a threshold voltage of the selected memory cell reaches a reference voltage, writing to the selected memory cell is completed by the controller,based on second data to be written to a memory cell adjacent to the selected memory cell at a time later than the first data, the controller changes the reference voltage used for the verify operation of the selected memory cell, andthe adjacent memory cell is connected to a word line adjacent to the selected word line.
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Abstract
A memory device capable of narrowing the threshold voltage distribution thereof includes word lines, bit lines, memory cells, a word line driver configured to apply voltage to a selected word line, a sense amplifier circuit configured to detect data of the memory cell, and a controller configured to control the word line driver and the sense amplifier. A write sequence includes a write operation in which write voltage is applied to the selected word line by the word line driver, and a verify operation in which, when a threshold voltage of the selected memory cell reaches a reference voltage, writing to the selected memory cell is completed. Based on second data that is written later than the first data to an adjacent memory cell adjacent to the selected memory cell, the controller changes the reference voltage used for completing the writing to the selected memory cell.
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Citations
16 Claims
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1. A semiconductor memory device, comprising:
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a plurality of word lines; a plurality of bit lines; a plurality of memory cells at intersections of the word lines and the bit lines; a word line driver configured to apply a voltage to a selected word line among the plurality of word lines; a sense amplifier circuit configured to detect the data of at least one of the memory cells; and a controller configured to control the word line driver and the sense amplifier, wherein a write sequence for writing first data to a selected memory cell connected to the selected word line includes a write loop that includes a write operation in which a write voltage is applied to the selected word line by the word line driver, and a verify operation during which, when a threshold voltage of the selected memory cell reaches a reference voltage, writing to the selected memory cell is completed by the controller, based on second data to be written to a memory cell adjacent to the selected memory cell at a time later than the first data, the controller changes the reference voltage used for the verify operation of the selected memory cell, and the adjacent memory cell is connected to a word line adjacent to the selected word line. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A semiconductor memory device, comprising:
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a plurality of word lines; a plurality of bit lines; a plurality of memory cells at intersections of the word lines and the bit lines; a word line driver configured to apply a voltage to a selected word line among the plurality of word lines; a sense amplifier circuit configured to detect the data of at least one of the memory cells; and a controller configured to control the word line driver and the sense amplifier, wherein a write sequence for writing first data to a selected memory cell connected to the selected word line includes a write loop that includes a write operation in which a write voltage is applied to the selected word line by the word line driver, and a verify operation during which, when a threshold voltage of the selected memory cell reaches a reference voltage, writing to the selected memory cell is completed by the controller, based on second data to be written to a memory cell adjacent to the selected memory cell at a time later than the first data, the controller changes the reference voltage used for the verify operation of the selected memory cell, the adjacent memory cell is connected to an adjacent bit line adjacent to at least one side of a selected bit line connected to the selected memory cell, and the controller is configured to reduce the reference voltage used in the verify operation of the selected memory cell based on the second data. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A semiconductor memory device, comprising:
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a plurality of word lines; a plurality of bit lines; a plurality of memory cells at intersections of the word lines and the bit lines; a word line driver configured to apply a voltage to a selected word line among the plurality of word lines; a sense amplifier circuit configured to detect the data of at least one of the memory cells; and a controller configured to control the voltage applied to a memory cell by the word line driver in a plurality of steps, wherein each step has a greater voltage level than a prior step, and to control the voltage sensed in a memory cell by the sense amplifier, wherein a write sequence for writing first data to a selected memory cell connected to the selected word line includes a write loop that includes a write operation in which a write voltage is applied to the selected word line by the word line driver, and a verify operation in which, when a threshold voltage of the selected memory cell reaches a reference voltage, writing to the selected memory cell is completed by the controller, and the controller is configured to modify the final voltage applied by the driver to a first memory cell located at an intersection of a word line and a bit line based upon the highest voltage to be later applied to a second memory cell at an adjacent intersection of a word line and a bit line. - View Dependent Claims (15, 16)
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Specification