Memory device and operating method thereof

Abstract

A memory device including: a memory block including a word lines, word lines located in the middle of the word lines are used as dummy word lines, a control circuit establish word lines stacked on one side and other side of the dummy word lines into a first and second sub-blocks, respectively, performs an independent erase operation on one of the first and second sub-blocks in an erase operation period, and a control logic differently sets a level of a first transfer voltage for controlling transfer of an erase common voltage to the selected sub-block and the level of a second transfer voltage for controlling transfer of the erase common voltage to the unselected sub-block, applies an erase allowable voltage from the erase common voltage to a word line of the selected sub-block, and floats a word line of the unselected sub-block, in the erase operation period.