| 摘要 |
PURPOSE:To prevent a decrease in dielectric strength by decreasing on-resistance without increasing the concentration of a vapor growth layer. CONSTITUTION:An N<-> type drain region 2, reverse conductivity type region 3, and N<+> type cource region 4 which are applied vapor growth are formed on an N<+> Si substrate 1 and in a longitudinal D-MOSFET consisting of a gate electrode 7, source electrode 8, and drain electrode 9, the dielectric strength at a junction 10 is determined by electrostatic concentration around a junction warped section 10' at the outside. The thickness t of the depletion layer is made equal to the minimum thickness t' of a projection-shaped buried region 21 and the opposite conductivity type region 3. In this way, the electric field at the part 22 will not be higher than that at the breakdown of the section 10' and the dielectric strength is decided by the part at 10' and is not decreased by the provision of the region 21. The region 21 is of N<+> type and can be maintained at a low resistance value. |
