NON-VOLATILE MEMORY DEVICE AND METHOD OF ERASING THE SAME

A non-volatile memory device includes a memory cell region including a first metal pad; a peripheral circuit region including a second metal pad and vertically connected to the memory cell region by the first metal pad and the second metal pad; a substrate in the memory cell region; a memory cell array in the memory cell region comprising a plurality of gate conductive layers stacked on the substrate and a plurality of pillars penetrating through the plurality of gate conductive layers and extending in a direction perpendicular to a top surface of the substrate, wherein at least one of the plurality of gate conductive layers is a ground select line; a control logic circuit in the peripheral circuit configured to output an erase enable signal for controlling an erase operation with respect to the memory cell array; a substrate bias circuit in the peripheral circuit configured to, in response to the erase enable signal, output a substrate bias voltage at a first target level to the substrate from a first time to a second time after the first time during a first delay period and, after the first delay period gradually increase a level of the substrate bias voltage to an erase voltage having a higher level than the first target level; and a row decoder in the peripheral circuit configured to apply a ground voltage to the ground select line based on control of the control logic circuit during the first delay period.