Semiconductor device having high breakdown voltage

摘要

A semiconductor body (100) has a first device region (20) of one conductivity type forming with a second device region (13) of the opposite conductivity type provided adjacent one major surface (11) of the semiconductor body (100) a first pn junction (40) which is reverse-biassed in at least one mode of operation. A floating further region (50) of the opposite conductivity type is provided within the first device region (20) remote from the major surfaces (11 and 12) of the semiconductor body (100) and spaced from the second device region (13) so that, in the one mode, the depletion region of the first pn junction (40) reaches the floating further region (50) before the first pn junction (40) breaks down. The floating further region (50) forms a further pn junction (51) with a highly doped capping region (60) of the one conductivity type which is provided within the first device region (20) between the floating further region (50) and the second device region (13) and spaced from the second device region (13) and which enables a high electric field to exist between the first pn junction (40) and the further floating region (50) with less risk of the device breaking down.