Patent ID: 8604563

Claim:
A semiconductor device comprising: a drain region of a field-effect transistor formed over a semiconductor substrate; a channel region of the field-effect transistor formed over the drain region; a source region of the field-effect transistor formed over the channel region; a trench reaching the drain region from an upper surface of the source region; a first insulating film formed in the trench and disposed at a lower part of the trench; a first gate electrode of the field-effect transistor formed over the first insulating film in the trench and disposed at the lower part of the trench; a second insulating film formed in the trench and disposed at a upper part of the trench; and a second gate electrode of the field-effect transistor formed over the second insulating film in the trench and disposed at the upper part of the trench, wherein a first lead-out part of the first gate electrode is formed in an outer peripheral portion of the trench and is electrically connected with the first gate electrode, wherein a second lead-out part of the second gate electrode is formed in the outer peripheral portion of the trench and is electrically connected with the second gate electrode, wherein a thickness of the first lead-out part is smaller than a thickness of the second lead-out part, wherein the first gate electrode and the first lead-out part include a first conductive film, respectively, wherein the second gate electrode and the second lead-out part include a second conductive film, respectively, wherein a thickness of the first gate electrode formed in the trench is smaller than a thickness of the second gate electrode formed in the trench, wherein the first gate electrode and the second gate electrode are electrically connected to a different potential, and wherein the first gate electrode and the source region are electrically connected to the same potential.