Method of controlling a carrier lifetime in a semiconductor switching device
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorTadaharu Minato
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Abstract
A semiconductor layer, through which a main current flows, is so structured that a carrier life time in the semiconductor layer is ununiform in accordance with a predetermined distribution of the carrier life time. Thus, turn OFF characteristics of a semiconductor switching device can be improved without causing any unacceptable disadvantages for other characteristics.
Claims10
A method of controlling a carrier life time in a semiconductor switching device having a cathode region and a gate region for switching a main current and a semiconductor layer through which said main current flows to the cathode region, comprising the steps of:
- preparing a semiconductor switching device and a radiation source for emitting a radiation;
- and
- irradiating said semiconductor switching device with said irradiation emitted from said radiation source only at a peripheral portion of said semiconductor layer aligned with said gate region to cause lattice defects only at the irradiated peripheral portion so that a central main current flowing portion in said semiconductor layer is different in carrier life time from the irradiated peripheral portion in said semiconductor layer.
Dependencies are inferred from the claim text.