A semiconductor device is provided with: a substrate; a first region provided above the substrate; a second region provided away from the first region in a first direction; a third region provided between the first region and the second region, the third region facing an electrode portion; a fourth region provided between the first region and the third region; and a fifth region provided between the second region and the third region. The fourth and fifth regions include carbon (C). Carbon concentrations in the first and second regions are lower than carbon concentrations in the fourth and fifth regions.