An NROM semiconductor memory device and fabrication method are disclosed. According to one aspect, a method for fabricating an NROM semiconductor memory device can include providing a plurality of u-shaped MOSFETs, which are spaced apart from one another and have a multilayer dielectric. The dielectric suitable for charge trapping along rows in a first direction and alone columns in a second direction in trenches of a semiconductor substrate. Source/drain regions are provided between the u-shaped MOSFETs in interspaces between the rows which run parallel to the columns. Isolation trenches are provided in the source/drain regions between the u-shaped MOSFETs of adjacent columns as far as a particular depth in the semiconductor substrate. The isolation trenches are filled with an insulation material. Word lines are provided for connecting respective rows of u-shaped MOSFETs.