| 摘要 |
PURPOSE:To restrain a part of a semiconductor pellet in contact with an electrode member from increasing in heat release value and to improve a semiconductor device in breakdown strength by a method wherein the crystal defect density in a semiconductor pellet surface is so distributed as to shorten the carrier life time of its heat releasing part not in contact with an electrode member compared with that of its part in contact with the electrode member. CONSTITUTION:The whole face of a semiconductor pellet 10 is uniformly irradiated with an electron beam to be low enough in carrier life time, and a semiconductor device is set to nearly a target value in electrical properties. Then, a part of the semiconductor pellet 10 other than a heat releasing part which is in contact with an electrode member 14 and possessed of an sufficient heat-dissipating effect is irradiated with an electron beam in a dose nearly ten times as much as that in which the whole face has been uniformly irradiated. At this point, a part A locally irradiated with an electron beam is low in heat dissipating property but has a crystal defect density 1.5 times or more as large as that of the heat dissipating part of the pellet 10 in contact with the electrode member 14, where the crystal defect density functions as a carrier recombining center. By this setup, the part A irradiated with the electron beam is decreased enough in carrier life time as compared with the heat releasing part in contact with the electrode member 14, so that it is restrained from increasing in heat release value and can be improved in back power resistance at reverse recovery. |
