| 摘要 |
PROBLEM TO BE SOLVED: To have a reverse recovery characteristic in which a loss is small, at a breakdown voltage of necessary minimum limit by a method wherein a cathode layer (n+) is formed as an uneven form, and n base layer is so structured that a thick region and a thin region are alternately disposed. SOLUTION: This diode comprises a p layer 10 to be an anode layer on a main surface of an n- base layer 10; a deep n1+ layer 12 to be a first cathode layer disposed so as to be equally spaced on an opposite surface side; a shallow n2+ layer 13 to be a second cathode layer disposed uniformly on a composite surface side; an anode electrode 14 ohmic-connected to the p+ layer 11; and a cathode electrode 15 ohmic-connected to the n2+ layer 13. At the time of conduction, holes are injected from the p layer 11 to the n- base layer 10, and electrons are injected from the deep n1+ and the shallow n2+ layer 13 to the n- base layer 10, respectively. At the time of reverse recovery, the holes in a thin region where a depletion layer spreads are swept out to the anode electrode 14, and the holes remain in an n- base region which is pinched between the n1+ layers 12 and disappear due to re-coupling.
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