| 摘要 |
<p>57 A reverse blocking type semiconductor device capable of being rapidly turned off is disclosed in which a semiconductor substrate (1) includes four semiconductor layers (2, 3, 4, 5) in a region sandwiched between a pair of principal surfaces in such a manner that adjacent ones of these layers (2, 3, 4, 5) are different in conductivity type from each other, one outermost layer (5) of the layers (2, 3, 4, 5) is surrounded by the layer (4) adjacent to one outermost layer (5), one outermost layer (5) and the layer (4) adjacent thereto are exposed to one principal surface, a cathode electrode (7) is kept in low-resistance contact with one outermost layer (5), a gate electrode (8) is kept in low-resistance contact with the layer (4) adjacent to one outermost layer (5) and lies in close proximity to one outermost layer (5), an anode electrode (6) is kept in low-resistance contact with the other outermost layer (2) at the other principal surface, and a main operating region of the other outermost layer (2) has an impurity concentration gradient in a direction parallel to the anode electrode (6).</p> |
