A semiconductor substrate of any one of a first conductivity type and a second conductivity type includes a first main surface and a second main surface. A first semiconductor layer of the first conductivity type is provided on the first main surface. A second semiconductor layer of the second conductivity type is provided on the first main surface. A first electrode is electrically connected to the first semiconductor layer. A second electrode is electrically connected to the second semiconductor layer. An insulating layer comprises silicon nitride and is arranged between the first semiconductor layer and the second semiconductor layer in an overlap region where the second semiconductor layer is provided above the first semiconductor layer. An anti-diffusion film is arranged between the insulating layer and the first semiconductor layer and is configured to prevent nitrogen from diffusing from the insulating layer into the first semiconductor layer.