Abstract: According to one embodiment, a memory device includes a string unit including a plurality of memory cell transistors which are connected in series, a first select transistor connected to a first end of the plurality of memory cell transistors, and a second select transistor connected to a second end of the plurality of memory cell transistors; and a bit line connected to the first select transistor.

Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.

Abstract: For data erase from an electrically erasable and programmable non-volatile memory cell, the following operations are performed: an erase operation to apply an erase pulse voltage to a memory cell for data erase, an erase verify operation to verify whether data erase is completed, and a step-up operation to increase the erase pulse voltage by a certain step-up voltage if data erase is not completed. A control unit controls voltages so that at least a first erase pulse voltage initially generated in the erase operation has a longer rise time than that of a second erase pulse voltage generated subsequent to the first erase pulse voltage.

Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.

Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.

Abstract: For data erase from an electrically erasable and programmable non-volatile memory cell, the following operations are performed: an erase operation to apply an erase pulse voltage to a memory cell for data erase, an erase verify operation to verify whether data erase is completed, and a step-up operation to increase the erase pulse voltage by a certain step-up voltage if data erase is not completed. A control unit controls voltages so that at least a first erase pulse voltage initially generated in the erase operation has a longer rise time than that of a second erase pulse voltage generated subsequent to the first erase pulse voltage.

Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.

Abstract: According to one embodiment, a semiconductor memory includes memory cells, word lines connected to gate of memory cells arranged in a row direction, a control circuit which controls the operation of the memory cells. During k-level data writing to a selected cell, the control circuit applies the corrected unselect voltage in accordance with the result of the reading of data from the unselected cell connected to the adjacent word line to the adjacent word line and applies a read voltage to the selected word line to read (k?1)-level data from the selected cell, and the control circuit writes data to the selected cell in accordance with the read (k?1)-level and the k-level data to be written.

Abstract: A semiconductor memory device comprises: a memory cell array comprising memory cells, each memory cell being able to store multi-bit data; word-lines connected to the memory cells, the word-lines being arranged in a first direction; bit-lines arranged in a second direction crossing the first direction, the bit-lines reading data from the memory cell array; and a control circuit controlling the operation of the memory cell array. The control circuit performs a first write operation of applying a first write voltage between a selected word-line and a channel of a selected memory cell, then performs a verify operation of determining whether the first write operation is completed, and performs a second write operation of applying, if the write operation to the first threshold voltage is completed in the verify operation, a second write voltage lower than the first write voltage between the selected word-line and the channel.

Abstract: For data erase from an electrically erasable and programmable non-volatile memory cell, the following operations are performed: an erase operation to apply an erase pulse voltage to a memory cell for data erase, an erase verify operation to verify whether data erase is completed, and a step-up operation to increase the erase pulse voltage by a certain step-up voltage if data erase is not completed. A control unit controls voltages so that at least a first erase pulse voltage initially generated in the erase operation has a longer rise time than that of a second erase pulse voltage generated subsequent to the first erase pulse voltage.

Abstract: A semiconductor memory device comprises: a memory cell array comprising memory cells, each memory cell being able to store multi-bit data; word-lines connected to the memory cells, the word-lines being arranged in a first direction; bit-lines arranged in a second direction crossing the first direction, the bit-lines reading data from the memory cell array; and a control circuit controlling the operation of the memory cell array. The control circuit performs a first write operation of applying a first write voltage between a selected word-line and a channel of a selected memory cell, then performs a verify operation of determining whether the first write operation is completed, and performs a second write operation of applying, if the write operation to the first threshold voltage is completed in the verify operation, a second write voltage lower than the first write voltage between the selected word-line and the channel.

Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.

Abstract: For data erase from an electrically erasable and programmable non-volatile memory cell, the following operations are performed: an erase operation to apply an erase pulse voltage to a memory cell for data erase, an erase verify operation to verify whether data erase is completed, and a step-up operation to increase the erase pulse voltage by a certain step-up voltage if data erase is not completed. A control unit controls voltages so that at least a first erase pulse voltage initially generated in the erase operation has a longer rise time than that of a second erase pulse voltage generated subsequent to the first erase pulse voltage.

Abstract: A nonvolatile semiconductor memory device includes: a memory cell array including a memory string having plural series-connected memory transistors; plural word lines disposed to be connected to the memory transistor in the memory string; plural bit lines electrically connected to an end of the memory string; and a control circuit. When performing a write operation on the memory cell array, the control circuit applies a first voltage to a selected word line selected from the plural word lines, applies a second voltage smaller than the first voltage to an unselected word line rendered unselected from the word lines. Before lowering a voltage applied to the unselected word line from the second voltage to a third voltage smaller than the second voltage, it lowers a voltage applied to the selected word line from the first voltage to a fourth voltage smaller than the first voltage.

Abstract: A first non-selected word line including a word line adjacent to a selected word line is applied with a first write pass voltage. Furthermore, a second non-selected word line which is a non-selected word line excluding the first non-selected word line is applied with a second write pass voltage smaller than a program voltage. A control circuit, in the write operation, raises the first write pass voltage toward a first target value by executing a voltage raising operation having a first voltage rise width, X times, and raises the second write pass voltage toward a second target value by executing a voltage raising operation having a second voltage rise width, Y times. The first voltage rise width is larger than the second voltage rise width, and X times is fewer than Y times.

Abstract: A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.

Abstract: The disclosure describes a semiconductor memory device including a memory cell array and a control circuit. The memory cell array comprises a plurality of memory cells that each include a control gate and a charge accumulation layer and that each are configured to have a threshold set to be included in any of a plurality of threshold distributions, the memory cell being connected between a bit line and a source line. The control circuit, in at least one of a write verify operation and a read operation on a selected memory cell, applies to the control gate a control gate voltage to determine the threshold of the selected memory cell, the control gate voltage having a plurality of values respectively corresponded to the plurality of threshold distributions, and sets a voltage between the bit line and the source line based on the control gate voltage.

Abstract: A nonvolatile semiconductor memory device includes: a memory cell array including a memory string having plural series-connected memory transistors; plural word lines disposed to be connected to the memory transistor in the memory string; plural bit lines electrically connected to an end of the memory string; and a control circuit. When performing a write operation on the memory cell array, the control circuit applies a first voltage to a selected word line selected from the plural word lines, applies a second voltage smaller than the first voltage to an unselected word line rendered unselected from the word lines. Before lowering a voltage applied to the unselected word line from the second voltage to a third voltage smaller than the second voltage, it lowers a voltage applied to the selected word line from the first voltage to a fourth voltage smaller than the first voltage.

Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.

Abstract: A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value.