Abstract: In an example embodiment, a semiconductor substrate has a plurality of active regions separated by a plurality of trenches. A gate insulation film fills at least a portion of the trenches, and a conductive gate film is formed over the gate insulation film. In an example embodiment, the gate insulation film, may include a tunneling insulation film, a charge storage film, and a blocking insulation film. The example embodiment may also include field isolation films, which partially fill the trenches of the semiconductor substrate, such that the upper surfaces of the active regions or the substrate are higher than the upper surfaces of the field isolation films.