Semiconductor device
AssigneeMitsubishi Electric Corporation
InventorTetsuo TAKAHASHI
Life of this patent
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Abstract
In one surface of a semiconductor substrate, an n− layer, a p base layer, a p well layer, another p well layer, a channel stopper layer, an emitter electrode, a guard ring electrode, and a channel stopper electrode for example are formed. In the other surface of the semiconductor substrate, an n+ buffer layer, a p+ collector layer, and a collector electrode are formed. In a curved corner of the p well layer, a p low-concentration layer having a lower impurity concentration than the impurity concentration of the p well layer is formed from the surface to a predetermined depth.
Claims7
A semiconductor device conducting current between a first electrode formed on a first main surface of a semiconductor substrate and a second electrode formed on a second main surface of the semiconductor substrate, the semiconductor device comprising:
- the semiconductor substrate having said first main surface and said second main surface opposite to each other;
- a first region of a first conductivity type formed in said first main surface of said semiconductor substrate to extend from said first main surface to a first depth;
- a second region of a second conductivity type having a predetermined impurity concentration, having a planar pattern including a corner, and formed from a surface of a predetermined region in said first region to a second depth shallower than said first depth;
- a third region of the second conductivity type circumferentially surrounding said second region so that said third region is spaced from said second region, and formed from a surface of said first region to a third depth;
- the first electrode formed to be electrically connected to said second region;
- and
- the second electrode formed to contact said second main surface of said semiconductor substrate,
- in said corner of said second region, a low-impurity-concentration region having an effective impurity concentration lower than said predetermined impurity concentration being formed.
Dependencies are inferred from the claim text.