The present application discloses a method for fabricating a semiconductor device including providing a first stacking structure comprising a first controller die, and a plurality of first storage dies sequentially stacked on the first controller die; providing a second stacking structure comprising a second controller die, and a plurality of second storage dies sequentially stacked on the second controller die; bonding the first controller die onto a bottom die through a plurality of first interconnect units; and bonding the second controller die onto the bottom die through a plurality of second interconnect units. The plurality of first storage dies respectively comprise a plurality of first storage units configured as a floating array. The plurality of second storage dies comprise a plurality of second storage units respectively comprising an insulator-conductor-insulator structure.