Insulated gate field effect semiconductor device

The present invention relates to an insulated gate field effect semiconductor device, and more particularly, to an insulated gate field effect semiconductor device that reduces the on-state resistance to improve the stability of the potential of the substrate thereby reducing the leakage current between drain and source regions. The present invention is intended to form the adjacent trenches by bending them to make a widened portion and a narrowed portion on the substrate of the semiconductor inside the trenches shaped in stripes and to arrange the adjacent widened portions and the narrowed portions alternately to lay the body contact region in the widened portion. By this arrangement, the stability of the potential is improved and thus leakage current is decreased. Further, the on-state resistance can be decreased and an advantage in rule is achieved while improving the channel width per unit area.