Nonvolatile memory device and operation method thereof

An operation method of a nonvolatile memory device including a program string and an inhibit string sharing a string select line, a ground select line, and a plurality of wordlines, the operation method comprising:

• setting a voltage level of the plurality of wordlines to a first voltage;
• decreasing a voltage level of first and second wordlines among the plurality of wordlines to a second voltage;
• and
• increasing a voltage level of a target wordline, which is one of the plurality of wordlines and is located between the first and second wordlines, to a third voltage,
• wherein during performing the decreasing and increasing, among the plurality of wordlines, voltage levels of a first plurality of wordlines located between the first wordline and the string select line, and voltage levels of a second plurality of wordlines located between the second wordline and the ground select line, are maintained with the first voltage.

A nonvolatile memory device, comprising:

• a program string including first and second memory transistors, and a program memory transistor connected between the first and second memory transistors;
• an inhibit string including third and fourth memory transistors, and an inhibit memory transistor connected between the third and fourth memory transistors;
• and
• a row decoder configured to control a first wordline connected to the first and third memory transistors, a second wordline connected to the second and fourth memory transistors, and a target wordline connected to the program memory transistor and the inhibit memory transistor,
• wherein during a first time period in which the row decoder provides a program voltage to the target wordline:
• the row decoder is configured to provide a ground voltage to the first wordline and the second wordline, and a first channel potential level corresponding to the program memory transistor is lower than a second channel potential level corresponding to the inhibit memory transistor.