A semiconductor memory includes a first memory cell array in a first region of a substrate and a second memory cell array in a second region of the substrate. The first memory cell array includes cell strings, and each cell string includes non-volatile memory cells stacked in a direction perpendicular to the substrate. The second memory cell array includes volatile memory cells, and each volatile memory cell includes a select transistor and a capacitor. The capacitor includes at least one contact electrically connected with the select transistor and having a second height corresponding to a first height of each cell string, and at least one second contact supplied with a ground voltage, having a third height corresponding to the first height of each cell string, adjacent to the at least one first contact, and electrically disconnected with the at least one first contact.