High voltage semiconductor device having a novel edge contour

A semiconductor device comprising:

• a body of semiconductor material having first and second major opposing surfaces and a peripheral edge extending therebetween, said body initially having a one type conductivity;
• a first region having a second type conductivity extending within said body, said first region forming a first PN junction with said body at the interface therewith, said junction comprising an edge segment extending substantially perpendicular to said first surface, a bottom segment extending substantially parallel with said first surface and a radius segment connecting said edge segment and said bottom segment;
• a contoured portion of said edge, said contour beginning at said first surface in said first region and extending toward said second surface to a first terrace, said first terrace intersecting said edge segment of said first PN junction, said contour, from a point near said intersection, further extending toward said second surface to a second terrace, said contour being concave between said intersection and said second terrace.