| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a semiconductor device in which floating of a floating portion can be kept without reducing an element breakdown voltage. <P>SOLUTION: Annular buffer trenches 30 are provided to be located adjacently to gate trenches 23 in the longitudinal direction of the gate trenches 23 and separated from the gate trenches 23. An outer peripheral well terminal portion 29a of an outer peripheral well region 29 is located within a range surrounded by the buffer trenches 30. Accordingly, the outer peripheral well region 29 and a float layer 28 are separated from each other with no intersection therebetween, whereby floating of the float layer 28 can be maintained. Portions of the buffer trenches 30, which are located at the opposite side to the gate trenches 23 sides in the longitudinal direction of the gate trenches 23, are located in the outer peripheral well region 29, so that concentration of electric field on these portions of the buffer trenches 30 can be moderated. <P>COPYRIGHT: (C)2012,JPO&INPIT |
