This
semiconductor device comprises a
semiconductor substrate with a first
impurity type; a plurality of active areas formed in the
semiconductor substrate; an element isolation trench including a first trench part and a second trench part surrounding the plurality of active areas, the first trench part being extended from a surface of the semiconductor substrate to a
depth direction, the second trench part being extended from the center of a bottom surface of the first trench part to the
depth direction with a narrower width than the width of the first trench part in a width direction; an element isolation insulator film filled in the element isolation trench; a gate
electrode formed on the plurality of active areas via a
gate insulator film; a plurality of
diffusion layers with a second
impurity type formed in a surface of the plurality of active areas, the plurality of
diffusion layers being located on each side of the element isolation trench and separated each other on each side of the gate
electrode; and a channel stop region extended from the bottom surface of the second trench part to the
depth direction in a predetermined depth with the first
impurity type, the channel stop region having a higher impurity concentration than the impurity concentration of the semiconductor substrate.