Semiconductor device and method for manufacturing the same

A semiconductor device, comprising:

• a first electrode;
• a second electrode;
• a third electrode, a position of the third electrode in a first direction being between a position of the first electrode in the first direction and a position of the second electrode in the first direction, the first direction being from the first electrode toward the second electrode;
• a first semiconductor layer including Alx1Ga1-x1N (0≤x1<1) and including a first partial region, a second partial region, and a third partial region, a second direction from the first partial region toward the first electrode crossing the first direction, a direction from the second partial region toward the second electrode being aligned with the second direction, a direction from the third partial region toward the third electrode being aligned with the second direction;
• a second semiconductor layer including Alx2Ga1-x2N (0<x2≤1 and x1<x2), a portion of the second semiconductor layer being between the third partial region and the third electrode in the second direction;
• and
• a first insulating layer including a first insulating region, the first insulating region being between the third electrode and the portion of the second semiconductor layer in the second direction,
• a concentration of hydrogen in the first semiconductor layer being less than 1/10 of a concentration of magnesium in the first semiconductor layer.