Threshold value read method of nonvolatile semiconductor memory device and nonvolatile semiconductor memory device
AssigneeKabushiki Kaisha Toshiba
InventorKoji Hosono
Life of this patent
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Abstract
A threshold voltage read method of a nonvolatile semiconductor memory device is disclosed. The threshold voltage read method applies a first threshold voltage measuring read voltage to the word line with a selection gate kept in a nonconductive state and then makes the selection gate conductive to read out a threshold voltage of the first data at the time of reading out the threshold voltage of the first data. Then, it applies a second threshold voltage measuring read voltage to the word line with the selection gate kept in the conductive state to read out a threshold voltage of the second data at the time of reading out the threshold voltage of the second data.
Claims17
A method of operating a nonvolatile semiconductor memory device which includes a memory cell unit having a selection gate and memory cells, comprising:
- accepting a threshold voltage measuring read voltage from the outside of the device;
- and
- applying the threshold voltage measuring read voltage to a selected word line with the selection gate kept in the conductive state to read out data of the memory cells at the time of reading out the threshold voltage of the memory cells.
A method of operating a nonvolatile semiconductor memory device which includes a memory cell unit having a selection gate and memory cells, applies a first verify read voltage to a word line with the selection gate kept in a nonconductive state, then makes the selection gate conductive to verify first data, and changes the first verify read voltage to a second verify voltage with the selection gate kept in the conductive state to verify second data after the first data, comprising:
- applying a first threshold voltage measuring read voltage to the word line with the selection gate kept in the nonconductive state and then making the selection gate conductive to read out a threshold voltage of the first data at the time of reading out the threshold voltage of the first data;
- and
- applying a second threshold voltage measuring read voltage to the word line with the selection gate kept in the conductive state to read out a threshold voltage of the second data at the time of reading out the threshold voltage of the second data.
A nonvolatile semiconductor memory device comprising:
- a memory cell unit having a selection gate and memory cells, and
- a write control circuit which controls a write operation of writing data into the memory cell,
- wherein the write control circuit applies a first verify read voltage to a word line with the selection gate kept in a nonconductive state, then makes the selection gate conductive and changes the first verify read voltage to a second verify voltage with the selection gate kept in the conductive state at the verify read operation time, applies a first threshold voltage measuring read voltage to the word line with the selection gate kept in the nonconductive state and then makes the selection gate conductive at the time of reading out the threshold voltage of first data, and applies a second threshold voltage measuring read voltage to the word line with the selection gate kept in the conductive state at the time of reading out the threshold voltage of second data.
Dependencies are inferred from the claim text.