Semiconductor device and method for manufacturing same

A method of manufacturing a semiconductor device, comprising:

• forming a protective film on a second layer of a stacked body including a first layer formed of a first nitride semiconductor and the second layer provided on the first layer, the second layer being formed of a second nitride semiconductor having a wider bandgap than the first nitride semiconductor;
• forming a source electrode and a drain electrode in openings provided in the passivation film;
• forming a gate electrode in an opening provided in the protective film, the gate electrode being located between the source electrode and the drain electrode;
• and
• introducing fluorine into a first region in the second layer, the first region being located between the gate electrode and the drain electrode, a concentration of fluorine in the first region is higher than a concentration of fluorine in a portion underneath the gate electrode in the second layer.