Patent ID: 6975013

Claim:
A diode comprising: a first-conductivity-type first region having a first impurity concentration; a first-conductivity-type second region placed on said first region and having a second impurity concentration that is lower than said first impurity concentration, said first region and said second region constituting a semiconductor substrate; a generally ring-like second-conductivity-type third region formed in a surface layer of said second region; a first-conductivity-type fourth region formed in contact with a portion of said first region that is located below a portion of said second region that is surrounded by said third region, said fourth region having a lower resistivity than said second region; a first main electrode formed in contact with said first region; and a third main electrode which contacts with a surface of said semiconductor substrate located inside said third region, so as to form a Schottky junction, wherein said second region includes a first portion located on said fourth region, and a second portion located under said third region, said first portion having a smaller thickness than said second portion.