Pressed-contact type semiconductor device

摘要

A P⁺⁺-type first diffusion layer is formed by diffusing P-type impurities on a front side of an N^--type semiconductor substrate, and an N-type fourth diffusion layer which is shallower than the first diffusion layer is formed by diffusing N-type impurities on the front side, and a P-type second diffusion layer is locally formed in a ring-shape so as to be exposed on the lateral side by diffusing P-type impurities on the back side, and P-type impurities are diffused on the back side of the substrate and a P⁺-type third diffusion layer is locally formed so as to be distributed inward from the second diffusion layer and not to be exposed to the lateral side, and the P-type second diffusion layer and the P⁺-type third diffusion layer are formed in the two-stage structure, thereby various characteristics can be improved.