Nitride semiconductor device

A nitride semiconductor device, comprising:

• an electron transport layer;
• an electron supply layer that is positioned over the electron transport layer and has a bandgap greater than a bandgap of the electron transport layer;
• a gate layer positioned over a portion of the electron supply layer, and including an acceptor impurity;
• a gate electrode positioned over a portion of the gate layer;
• a passivation layer that covers the electron supply layer, the gate layer, and the gate electrode, and that includes a source opening and a drain opening;
• a source electrode in contact with the electron supply layer via the source opening;
• and
• a drain electrode in contact with the electron supply layer via the drain opening,
• wherein the source electrode includes a field plate section that covers the gate layer and the gate electrode, and the field plate section includes a field plate end section that is positioned between the gate layer and the drain electrode, and
• wherein the electron supply layer includes:
• a first recess that is formed in a top surface of the electron supply layer, and that overlaps the gate layer in a plan view;
• and
• a second recess that is formed in the top surface of the electron supply layer, and that overlaps the field plate end section in a plan view.