Nonvolatile semiconductor memory device and method for driving same

A nonvolatile semiconductor memory device comprising:

• a memory string having a plurality of memory cells;
• and
• a driving unit connected to the memory cells,
• each memory cell including:
• a semiconductor layer having a source region, a drain region and a channel provided between the source region and the drain region;
• a first insulating film provided on the channel;
• a charge retention layer provided on the first insulating film;
• and
• a gate electrode provided on the charge retention layer,
• in sequentially reading data stored in the memory cells by sequentially applying a first signal to each memory cell, a second signal being applied to a second cell when applying the first signal to a first cell, the first cell being one of the memory cells, the second cell being the memory cell of the memory cells except the first cell,
• prior to application of a fifth signal and a sixth signal, the driving unit being configured to apply a seventh signal to the gate electrode of a third cell, the fifth signal programming data in the third cell, the sixth signal verify-reading the programmed data, the third cell being at least one of the memory cells in the memory string,
• the seventh signal having a seventh signal voltage and a seventh signal time duration, an absolute value of the seventh signal voltage being smaller than an absolute value of a voltage of the fifth signal, the seventh signal time duration being equal to or more than a time duration during which the fifth signal and the sixth signal are applied to the third cell.

A method for driving a nonvolatile semiconductor memory device including:

• a memory string having a plurality of memory cells;
• and a driving unit connected to the memory cells, each memory cell including:
• a semiconductor layer having a source region, a drain region and a channel provided between the source region and the drain region;
• a first insulating film provided on the channel;
• a charge retention layer provided on the first insulating film;
• and a gate electrode provided on the charge retention layer, in sequentially reading data stored in the memory cells by sequentially applying a first signal to each memory cell, a second signal being applied to a second cell when applying the first signal to a first cell, the first cell being one of the memory cells, the second cell being the memory cell of the memory cells except the first cell, the method comprising:
• prior to the sequential reading,
• applying a third signal to the gate electrodes of all the memory cells included in the memory string;
• and
• in a period prior to the application of the third signal,
• performing at least one of:
• applying a fourth signal to the gate electrodes of all the memory cells included in the memory string;
• and
• matching a potential of the gate electrodes of all the memory cells included in the memory string with a potential of the semiconductor layer,
• the third signal having a third signal voltage and a third signal time duration, an absolute value of the third signal voltage being smaller than an absolute value of a voltage of the second signal and the third signal time duration being equal to or more than a time duration during which the first signal is applied to all the memory cells included in the memory string in sequential reading.

A method for driving a nonvolatile semiconductor memory device including:

• a memory string having a plurality of memory cells;
• and a driving unit connected to the memory cells, each memory cell including:
• a semiconductor layer having a source region, a drain region and a channel provided between the source region and the drain region;
• a first insulating film provided on the channel;
• a charge retention layer provided on the first insulating film;
• and a gate electrode provided on the charge retention layer, in sequentially reading data stored in the memory cells by sequentially applying a first signal to each memory cell, a second signal being applied to a second cell when applying the first signal to a first cell, the first cell being one of the memory cells, the second cell being the memory cell of the memory cells except the first cell, the method comprising:
• prior to application of a fifth signal and a sixth signal, applying a seventh signal to the gate electrode of a third cell, the fifth signal programming data in the third cell, the sixth signal verify-reading the programmed data, the third cell being at least one of the memory cells in the memory string,
• the seventh signal having a seventh signal voltage and a seventh signal time duration, an absolute value of the seventh signal voltage being smaller than an absolute value of a voltage of the fifth signal, the seventh signal time duration being equal to or more than a time duration during which the fifth signal and the sixth signal are applied to the third cell.