Semiconductor memory device, method for fabricating the same and electronic system including the same

Abstract

A semiconductor memory device may include a cell substrate including a cell array region and an extension region, a first mold structure on the cell substrate, a second mold structure on the first mold structure, a channel structure passing through the first and second mold structures on the cell array region, and a cell contact structure passing through the first and second mold structures on the extension region. The first mold structure and the second mold structure respectively include first gate electrodes and second gate electrodes sequentially stacked on the cell array region and stacked in a stepwise manner on the extension region. The cell contact structure includes a lower conductive pattern connected to one of the first gate electrodes, an upper conductive pattern connected to one of the second gate electrodes, and an insulating pattern separating the lower conductive pattern from the upper conductive pattern.