Terminal structure for power devices and method of fabrication

Abstract

The application relates to a terminal structure and a preparation method of a power device. In a terminal region, a depletion stop ring is arranged in the direction of a second conductive type VLD region of a main junction, wherein the depletion stop ring is distributed in the terminal region at least in the second conductive type VLD region; for any depletion stop ring, a plurality of interval distributed depletion stop grooves are arranged, and the groove bottom of the depletion stop groove is below the second conductive type VLD region; for any depletion stop groove, in-groove conductive polysilicon filled in the depletion stop groove and in-groove low dielectric insulator covering the inner wall of the depletion stop groove are arranged, and the in-groove conductive polysilicon is insulated and separated from the inner wall of the depletion stop groove through the in-groove low dielectric insulator. The application can effectively avoid the surface breakdown of the VLD region, eliminate the influence of the periphery of the main junction and the deviation of the injection dose of a production line machine on the breakdown voltage, and improve the reliability of the terminal.

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