Nonvolatile memory device and operating method thereof

A method for operating a nonvolatile memory device, comprising:

• applying a negative erase voltage to a control gate electrode of a memory cell;
• and
• applying a first voltage higher than the negative erase voltage to a channel through a source region to erase charges stored in the memory cell through F-N tunneling,
• wherein the nonvolatile memory device comprises:
• the channel vertically extending from a substrate;
• a plurality of memory cells stacked along the channel;
• the source region connected to a first end portion of the channel;
• and
• a bit line connected to a second end portion of the channel,
• wherein the first end portion of the channel is formed as an undoped semiconductor layer or a semiconductor layer doped with P-type impurities,
• wherein the second end portion of the channel is formed of a semiconductor material of which a conductivity type is different from that of the first end portion, and
• wherein an intermediate portion of the channel is provided between the first end portion and the second end portion and is formed of a semiconductor material of which a conductivity type is the same as that of the first end portion.