A semiconductor device includes a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type on the first semiconductor region, a third semiconductor region of the first conductivity type on the second semiconductor region, a control electrode disposed within and insulated from the first, second, and third semiconductor regions, a first electrode electrically connected with the second and third semiconductor regions, a second electrode, and a fourth semiconductor region of the second conductivity type between the second electrode and the first semiconductor region. The fourth semiconductor region includes a first portion having a first dopant concentration and a second portion having a second dopant concentration higher than the first dopant concentration, and a contact area of the first portion with the second electrode is larger than a contact area of the second area with the second electrode.