A 3D-NAND memory includes a transistor formed in a first side of a periphery circuit substrate, a memory cell stack formed over a first side of a cell array substrate, and a first connection structure formed over an opposing second side of the cell array substrate. The memory cell stack includes a doped region formed in the first side of the cell array substrate and coupled to the first connection structure through a first VIA, a common source structure that extends from the doped region toward the first side of the periphery circuit substrate, and a second connection structure that is positioned over and coupled to the common source structure. The first side of the cell array substrate and the first side of the periphery circuit substrate are aligned facing each other so that the transistor is coupled to the second connection structure.