Semiconductor memory device having vertical semiconductor films with narrowing widths and gate insulating films with different thickness

Abstract

A semiconductor memory device according to an embodiment includes: a substrate; a plurality of first gate electrodes; a first semiconductor film facing the plurality of first gate electrodes; and a first gate insulating film provided between the plurality of first gate electrodes and the first semiconductor film. Moreover, this semiconductor memory device includes: a plurality of second gate electrodes; a second semiconductor film facing the plurality of second gate electrodes; and a second gate insulating film provided between the plurality of second gate electrodes and the second semiconductor film. Moreover, this semiconductor memory device includes: a third gate electrode that is provided between the plurality of first gate electrodes and the plurality of second gate electrodes, and extends in a second direction; and a third gate insulating film provided between the third gate electrode and the first semiconductor film. Moreover, a thickness in a first direction of the third gate insulating film is larger than a width in the second direction of the first gate insulating film and the second gate insulating film.