Semiconductor memory device

A semiconductor memory device comprising:

• a substrate;
• first and second stacked structures spaced apart in a first direction on the substrate, and including semiconductor patterns stacked in a direction perpendicular to an upper surface of the substrate;
• bit lines in contact with first sides of the semiconductor patterns of the first and second stacked structures and extending in a first direction parallel to the upper surface of the substrate;
• common source lines in contact with second sides of the semiconductor patterns of the first and second stacked structures and extending in the first direction;
• a plurality of first word lines penetrating the first stacked structure;
• a plurality of second word lines penetrating the second stacked structure;
• first data storage patterns between the first word lines and the first stacked structure;
• and
• second data storage patterns between the second word lines and the second stacked structure.