Semiconductor device

A semiconductor device comprising:

• an active region which is disposed on a first main surface side of a substrate to apply a current actively or passively;
• a first conductivity-type low-resistivity layer which is disposed on a second main surface side of the substrate;
• a vertical drift portion which is disposed between the active region and the low-resistivity layer so that a drift current flows into the vertical drift portion vertically in the ON state while the vertical drift portion is depleted in the OFF state, and which forms a first parallel pn structure in which a first vertical first conductivity-type region oriented in a thickness direction of the substrate and a first vertical second conductivity-type region oriented in the thickness direction of the substrate alternate repeatedly;
• an edge termination region which is provided around the vertical drift portion and disposed between the first main surface and the low-resistivity layer, so that the edge termination region substantially serves as a region in which current does not flow in the ON state while the edge termination region is depleted in the OFF state;
• a first conductivity-type layer which is provided between the first parallel pn structure and the low-resistivity layer so as to extend from the active region to the edge termination region and which has higher resistivity than the low-resistivity layer;
• and
• a second conductivity-type layer which is provided selectively inside the first conductivity-type layer in the edge termination region.