Semiconductor device

A semiconductor device, comprising:

• a first electrode;
• a second electrode;
• a third electrode including a first electrode portion, a position of the third electrode in a first direction from the first electrode to the second electrode being between a position of the first electrode in the first direction and a position of the second electrode in the first direction;
• a first semiconductor layer including Alx1Ga1-x1N (0≤x1<1), the first semiconductor layer including a first partial region, a second partial region, a third partial region, a fourth partial region, and a fifth partial region, a second direction from the first partial region to the first electrode crossing the first direction, a direction from the second partial region to the second electrode being along the second direction, a direction from the third partial region to the first electrode portion being along the second direction, a position of the fourth partial region in the first direction being between a position of the first partial region in the first direction and a position of the third partial region in the first direction, a position of the fifth partial region in the first direction being between the position of the third partial region in the first direction and a position of the second partial region in the first direction;
• a second semiconductor layer including Alx2Ga1-x2N (0<x2<1, x1<x2), the second semiconductor layer including a first semiconductor portion and a second semiconductor portion, a direction from the fourth partial region to the first semiconductor portion being along the second direction, a direction from the fifth partial region to the second semiconductor portion being along the second direction;
• and
• a compound member including Alz1Ga1-z1N (0<z1≤1, x2<z1), the compound member including a first region, a second region, and a third region, the first region being between the fourth partial region and the first electrode portion in the first direction, the second region being between the first electrode portion and the fifth partial region in the first direction, the third region being between the third partial region and the first electrode portion, a first absolute value of a first difference between a (10-10) inter-plane spacing in the first region and a (10-10) inter-plane spacing in the fourth partial region being greater than a third absolute value of a third difference between a (10-10) inter-plane spacing in the third region and a (10-10) inter-plane spacing in the third partial region.