Hemt semiconductor device with a AlInGaN layer for polarity control

A semiconductor device, comprising:

• a first electrode;
• a second electrode;
• a third electrode, 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 layer including SiC, the first layer including a first partial region, a second partial region, a third partial region, a fourth partial region and a fifth partial region, a direction from the first partial region to the first electrode being along a second direction 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 third electrode being along the second direction, the fourth partial region being located between the first partial region and the third partial region in the first direction, the fifth partial region being located between the third partial region and the second partial region in the first direction;
• a second layer including AlxInyGa1-x-yN (x+y=1, 0≤x<1, 0≤y≤1), the second layer including a first compound region provided between the third partial region and the third electrode;
• a third layer including AlzGa1-zN (x<z≤1), the third layer including a first portion, a second portion, and a third portion, a direction from the fourth partial region to the first portion being along the second direction, a direction from the fifth partial region to the second portion being along the second direction, the third portion being located between the third partial region and the first compound region, the third layer contacting the first layer;
• and
• an insulating member including a first insulating region, the first insulating region being located between the first compound region and the third electrode,
• the second layer not including a region overlapping the fourth partial region in the second direction, and not including a region overlapping the fifth partial region in the second direction, or
• the second layer including a second compound region and a third compound region, a direction from the fourth partial region to the second compound region and a direction from the fifth partial region to the third compound region being along the second direction, a first thickness of the first compound region along the second direction being thicker than a second thickness of the second compound region along the second direction, and thicker than a third thickness of the third compound region along the second direction,
• wherein the first thickness is thicker than a thickness of the third portion along the second direction,
• a value of z is 0.8 or more,
• a value of x is not less than 0.01 and not more than 0.5, and
• a thickness of the third portion along the second direction is not less than 2 nm and not more than 4 nm.