High voltage semiconductor structure and method

A high voltage semiconductor structure including in combination:

• a semiconductor substrate of a first conductivity type;
• a first region disposed at a first surface of said semiconductor substrate to provide a main rectifying junction;
• a second region of a second conductivity type formed at said first surface of said semiconductor substrate and surrounding said first region, said second region forming a p-n junction between said second region and said semiconductor substrate having a maximum depth below said first surface;
• and
• a third region of said second conductivity type formed at said first surface of said semiconductor substrate, said third region having reduced conductivity compared to said second region, said third region in contact with a first side of said second region, said third region forming a p-n junction between said third region and said semiconductor substrate having a maximum depth below said first surface greater than said maximum depth of said p-n junction between said second region and said semiconductor substrate.