Edge terminal structure of high-voltage power semiconductor device

Abstract

The invention discloses an edge terminal structure of a high-voltage power semiconductor device. The edge terminal structure comprises a plurality of field limiting rings which surround the power semiconductor device and have the conduction type opposite to that of a substrate, wherein doping regions which have the same conduction type as the field limiting rings and lower doping density than the field limiting rings are arranged around the field limiting rings; the field limiting rings are wrapped by the doping regions and coated by field plates; and the field limiting rings are separated from the field plates by using silicon dioxide layers. The field plates can be made of copper, aluminum, polycrystalline silicon, oxygen-doped polycrystalline silicon and the like. Because the doping regions with lower density are arranged around the conventional field limiting rings, the density of edge cell electric field lines can be effectively reduced, the electric field strength born by an edge cell is reduced, the breakdown voltage is increased, the area efficiency of the edge terminal structure is effectively improved, the chip area is saved and the chip cost is reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to an edge terminal structure of a high-voltage power semiconductor device. Background technique [0002] Power semiconductor devices, such as vertical double diffused field effect transistor (VDMOS), insulated gate bipolar transistor (IGBT), etc., are often composed of several cells connected in parallel in order to obtain a certain current capability. Since cell-to-cell depletion is formed among each other, breakdown is not easy to occur. However, the edge cell (also known as the transition region or the main junction) has dense electric field lines due to the small curvature radius of the depletion layer edge, and its electric field strength is much higher than that in the body, so the breakdown voltage will be much lower than in the body, and the breakdown first Occurs on the surface of edge cells. Therefore, a special structure should be adopted to protect the e...

AI Technical Summary

Problems solved by technology

Generally speaking, the withstand voltage will increase with the increase of the number of field limiting rings. However, the increase in the number of field limiting rings will also increase the occupied chip area, which will increase the cost of the chip.

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