Semiconductor device, power circuit, and computer

A semiconductor device comprising:

• a nitride semiconductor layer;
• a gate electrode;
• and
• an insulating layer provided between the nitride semiconductor layer and the gate electrode, the insulating layer including an oxide film or an oxynitride film contacting the nitride semiconductor layer, the oxide film or the oxynitride film including carbon (C) and at least one impurity selected from the group consisting of boron (B), gallium (Ga), aluminum (Al), and indium (In),
• wherein a first peak of a concentration distribution of the at least one impurity in the insulating layer is present in the oxide film or the oxynitride film,
• a second peak of a concentration distribution of carbon in the insulating layer is present in the oxide film or the oxynitride film,
• a distance between the first peak and the nitride semiconductor layer is equal to or less than 5 nm, and
• a distance between the second peak and the nitride semiconductor layer is equal to or less than 5 nm.

A semiconductor device comprising:

• a nitride semiconductor layer;
• a first electrode contacting the nitride semiconductor layer;
• a second electrode contacting the nitride semiconductor layer;
• a gate electrode provided between the first electrode and the second electrode;
• and
• an insulating layer provided between the gate electrode and the first electrode or between the gate electrode and the second electrode, the insulating layer including an oxide film or an oxynitride film contacting the nitride semiconductor layer, the oxide film or the oxynitride film including carbon (C) and at least one impurity selected from the group consisting of boron (B), gallium (Ga), aluminum (Al), and indium (In),
• wherein a first peak of a concentration distribution of the at least one impurity in the insulating layer is present in the oxide film or the oxynitride film,
• a second peak of a concentration distribution of carbon in the insulating layer is present in the oxide film or the oxynitride film,
• a distance between the first peak and the nitride semiconductor layer is equal to or less than 5 nm, and
• a distance between the second peak and the nitride semiconductor layer is equal to or less than 5 nm.