A method for fabricating memory devices includes forming a first portion of a memory device that includes a first device portion and one or more first interface portions. The first device portion includes a plurality of first memory strings, each of which includes a plurality of first memory cells vertically separated from one another. Each of the one or more first interface portions, laterally abutted to one side of the first device portion, includes a plurality of first word lines (WLs). The method further includes forming a plurality of first source lines (SLs) and a plurality of first bit lines (BLs) in the first device portion. The method further includes forming a first seal ring structure that laterally encloses both the first device portion and the first interface portion concurrently with forming the pluralities of SLs and BLs.