A life time control by ion irradiation is often performed in a so-called reverse conducting insulated gate bipolar transistor (RC-IGBT) including an IGBT and a diode provided to a same semiconductor substrate.
In a semiconductor device described in Patent Literature 1, ions are radiated intensively to a diode cell. In comparison with a case where ions are radiated across an entire surface of the semiconductor substrate, a life time in the diode cell can be controlled while an ON voltage of the IGBT can be decreased. In the semiconductor device, an ion irradiation portion protrudes from the diode cell into an IGBT cell to restrict a charge injection from the IGBT cell to the diode cell using a lattice defect layer provided by ion irradiation. A switching loss and a recovery loss can be thus reduced.
However, a reducing effect on switching loss and recovery loss is not exerted sufficiently when a protrusion amount of the lattice defect layer provided by ion irradiation into the IGBT cell is small. Conversely, when a protrusion amount of the lattice defect layer into the IGBT cell is large, characteristics of an ON voltage may possibly deteriorate.
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