Superjunction device with improved avalanche capability and breakdown voltage

Abstract

A superjunction device has a plurality of equally spaced P columns in an N − epitaxial layer. The concentration of the P type columns is made greater than that needed for maintaining charge balance in the N − epi region and the P columns thereby to increase avalanche energy. An implant dose of 1.1E13 or greater is used to form the P columns.

What is claimed is:  
     
         1 . A super unction device comprising a flat thin monocrystalline silicon die having an N +  body and a junction-receiving epitaxially grown N −  layer on top of said N +  body; 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 change balance between said P columns and the surrounding N −  epitaxial silicon.  
     
     
         2 . The device of  claim 1 , which further includes a MOSgate structure formed on the top surface of said N −  epitaxial layer of silicon.  
     
     
         3 . The device of  claim 2 , wherein said MOSgate structure includes 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 N −  epitaxial silicon.  
     
     
         4 . The device of  claim 1 , wherein said P column is formed from boron implants having a dose of greater than about 1.1E13.  
     
     
         5 . The device of  claim 2 , wherein said P column is formed from boron implants having a dose of greater than about 1.1E13.  
     
     
         6 . The device of  claim 3 , wherein said P column is formed from boron implants having a dose of greater than about 1.1E13.