| 摘要 |
A high-power MOSFET has a multiplicity of hexagonal base regions which are formed in the surface of a semiconductor chip and incorporate respective hexagonal annular source regions. The base regions are relatively shallow and are composed of a material having a relatively low conductivity. A central region of each of the base regions extends to the upper surface of the chip and makes contact with a planar source electrode, which also makes contact with the source regions. The central regions of the base elements which make contact with the source electrode have, over a section extending directly underneath the source regions, a higher conductivity than the main base section. The base regions are formed by an ion implantation through a gate oxide which is exposed by a window in the polysilicon layer on top thereof. After the ion implantation and the driving-in of the base regions, an annular source region is diffused into each base, and in this process, the same polysilicon window is used as the external mask. An oxide point situated in the centre can be left in the centre of each of the open windows so that the oxide is thicker in the central regions and remains in position during the diffusion of the source regions.
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