DIODE AND POWER CONVERTOR USING THE SAME

A diode includes an anode electrode layer 600; a cathode electrode layer 500; a buffer layer 111 of a first conductivity type formed between the anode electrode layer 600 and the cathode electrode layer 500 in a region extending to a location at a distance of 30 µm or more from the cathode electrode layer 500; a first semiconductor layer 110 of the first conductivity type formed in a region between the anode electrode layer 600 and the cathode electrode layer 500, and being in contact with the buffer layer of the first conductivity type; and a second semiconductor layer 120 of a second conductivity type formed in a region between the anode electrode layer and the first semiconductor layer of the first conductivity type. The carrier concentration in the first semiconductor layer is lower than the carrier concentration in the buffer layer. The carrier concentration in the buffer layer is less than 1×10 15 cm -3 . Carrier injection from the cathode electrode layer into the first semiconductor layer is suppressed either by means of a low carrier lifetime control layer included in the buffer layer or by means of a further semiconductor region of the first conductivity type in a partial region between the cathode electrode layer and the buffer layer.