US Patent 7768093 Power semiconductor device

A semiconductor device has a heavily doped substrate and an upper layer with doped silicon of a first conductivity type disposed on the substrate, the upper layer having an upper surface and including an active region that comprises a well region of a second, opposite conductivity type. An edge termination zone has a junction termination extension (JTE) region of the second conductivity type, the region having portions extending away from the well region and a number of field limiting rings of the second conductivity type disposed at the upper surface in the junction termination extension region.