SEMICONDUCTOR DEVICE

A semiconductor device includes a semiconductor substrate, a first semiconductor layer on the semiconductor substrate, a second semiconductor layer on the first semiconductor layer, a first electrode on the second semiconductor layer, a second electrode arranged with the first electrode along a front surface of the second semiconductor layer, a third electrode between the first and second electrodes on the second semiconductor layer, a metal layer on a back surface of the semiconductor substrate at a side opposite to the first semiconductor layer, and a conductor extending inside the semiconductor substrate and electrically connecting the first electrode and the metal layer via the second semiconductor layer. The second semiconductor layer includes a first region including a first-conductivity-type impurity, and a second region including a first-conductivity-type impurity with a higher concentration than the first region; and the second region is between the conductor and the first electrode.