THREE-DIMENSIONAL SEMICONDUCTOR MEMORY DEVICE AND METHOD OF FABRICATING THE SAME

Disclosed is a semiconductor memory device comprising a second substrate on a first substrate and including a lower semiconductor layer and an upper semiconductor layer on the lower semiconductor layer, an electrode structure on the upper semiconductor layer and including a plurality of stacked electrodes, a vertical channel structure that penetrates the electrode structure and is connected to the second substrate, an interlayer dielectric layer that covers the electrode structure, and a cutting structure that penetrates the interlayer dielectric layer and the upper semiconductor layer. The upper semiconductor layer has a first sidewall defined by the cutting structure. The lower semiconductor layer has a second sidewall adjacent to the first sidewall. The first sidewall and the second sidewall are horizontally offset from each other.