Semiconductor device

The invention provides a semiconductor device, and the device can soften a current waveform during the reverse recovery of a high-speed diode. The device is locally provided with a carrier residual layer (crystallization defect layer) which generates carriers in a region of a drift layer at the outer side of a depletion layer formed during the application of a reverse voltage in a diode with a PiN-type diode structure enabling a current to flow upwards in a vertical direction. The device supplies the carriers during the switching of the layer, and generates current flow. Therefore, the carriers cannot disappear suddenly, and the device can soften the current waveform during the reverse recovery. Because the back surface of the diode is not provided with the carrier residual layer (crystallization defect layer), the device can soften the current waveform without enabling Vf to rise.