Nonvolatile semiconductor memory device and method for driving same

A method for driving a nonvolatile semiconductor memory device, the device including:

• a substrate;
• a stacked body provided on the substrate, the stacked body including a plurality of insulating films alternately stacked with a plurality of electrode films, a through-hole being made in the stacked body to align in a stacking direction;
• a semiconductor pillar buried in an interior of the through-hole;
• and a charge storage film provided between the electrode film and the semiconductor pillar, a diameter of the through-hole differing by a position in the stacking direction, the method comprising:
• when applying a potential to the electrode film, supplying a potential to reduce a potential difference with the semiconductor pillar as a diameter of the through-hole piercing the electrode film decreases.

A nonvolatile semiconductor memory device comprising:

• a semiconductor substrate;
• a source line provided above the semiconductor substrate;
• a bit line provided above the source line;
• a memory string including
• a first selection transistor connected to the bit line,
• a second selection transistor connected to the source line, and
• a plurality of electrically-series-connected memory transistors connected between the first selection transistor and the second selection transistor, the memory transistors including
• a first memory cell transistor being above the semiconductor substrate,
• a second memory cell transistor being above the first memory cell transistor, and
• a third memory cell transistor being above the second memory cell transistor;
• a first word line being above the semiconductor substrate and electrically connected to a gate of the first memory cell transistor;
• a second word line being above the first word line and electrically connected to a gate of the second memory cell transistor;
• a third word line being above the second word line and electrically connected to a gate of the third memory cell transistor;
• a driver circuit configured to apply voltages to the first to third word lines, respectively;
• and
• a control circuit configured to perform a read operation on a condition that
• the driver circuit applies a second voltage to the second word line and applies a third voltage which is higher than the second voltage to the third word line when a read operation for the first memory cell transistor is performed,
• the driver circuit applies a first voltage which is lower than the second voltage to the first word line and applies the third voltage to the third word line when a read operation for the second memory cell transistor is performed, and
• the driver circuit applies the first voltage to the first word line and applies the second voltage to the second word line when a read operation for the third memory cell transistor is performed.

A nonvolatile semiconductor memory device, comprising:

• a substrate;
• a first electrode film provided on the substrate, the first electrode film being spaced from the substrate;
• a second electrode film provided on the first electrode film, the second electrode film being positioned above and spaced from the first electrode film;
• a third electrode film provided on the second electrode film, the third electrode film being positioned above and spaced from the second electrode film;
• a semiconductor pillar intersecting the first electrode film, the second electrode film and the third electrode film, a first portion of the semiconductor pillar being disposed in the first electrode film, a second portion of the semiconductor pillar being disposed in the second electrode film and a third portion of the semiconductor pillar being disposed in the third electrode film, a first diameter of the first portion being smaller than a second diameter of the second portion, and the second diameter being smaller than a third diameter of the third portion;
• a bit line connected to the semiconductor pillar above the third electrode film;
• a charge storage film provided between the semiconductor pillar and the first electrode film, between the semiconductor pillar and the second electrode film and between the semiconductor pillar and the third electrode film;
• and
• a drive circuit supplying a first potential to the first electrode film, supplying a second potential to the second electrode film and supplying a third potential to the third electrode film, the first potential being lower than the second potential, and the second potential being lower than the third potential.

A method for driving a nonvolatile semiconductor memory device, the device including:

• a first memory cell transistor being above a semiconductor substrate;
• a second memory cell transistor being above the first memory cell transistor;
• a third memory cell transistor being above the second memory cell transistor;
• a first word line electrically connected to a gate of the first memory cell transistor;
• a second word line electrically connected to a gate of the second memory cell transistor;
• a third word line electrically connected to a gate of the third memory cell transistor, a bit line;
• a source line;
• a first selection transistor connected to the bit line;
• a second selection transistor connected to the source line;
• the first to third memory cell transistors connected between the first and second selection transistors;
• the first selection transistor being above the third memory cell transistor;
• and a driver circuit, the method comprising using the driver circuit to:
• apply a second voltage to the second word line and apply a third voltage to the third word line when a read operation for the first memory cell transistor is performed;
• apply a first voltage to the first word line and apply the third voltage to the third word line when a read operation for the second memory cell transistor is performed;
• and
• apply the first voltage to the first word line and apply the second voltage to the second word line when a read operation for the third memory cell transistor is performed,
• wherein the first voltage is lower than the second voltage, and the second voltage is lower than the third voltage.