Superjunction device with improved avalanche capability and breakdown voltage

A superjunction device comprising a flat thin monocrystalline silicon die having an N+ body and a junction-receiving epitaxially grown— layer on top of said N+ body;

• a MOSgate structure formed on the top surface of said— epitaxial layer of silicon;
• said MOSgate structure including a source region in the top of each of said P columns and defining invertible channel regions in said P columns and a gate structure spanning across said invertible channel regions and said— epitaxial silicon;
• and a means for increasing the avalanche energy of the superjunction device without affecting its breakdown voltage, said means being comprised of a plurality of equally spaced P type columns of similar cross-section extending into said epitaxial layer for a substantial portion of the thickness of said epitaxial layer and perpendicularly to the top and bottom surfaces of said die;
• said P type columns having a P type concentration which is intentionally greater than that needed for charge balance between said P columns and the surrounding— epitaxial silicon.