Method of manufacturing group iii-nitride semiconductor

A method of manufacturing a group III-nitride semiconductor comprising:

• a loading step in which a substrate is loaded into a chamber;
• a pressure reduction step in which a suction unit reduces a pressure in the chamber;
• a heating step in which a heater provided in the chamber heats the substrate;
• a first film forming step in which a first gas supply unit supplies an organic metal gas containing a group III element to the substrate in the chamber, a second gas supply unit supplies a first gas containing hydrogen gas and nitrogen gas to a plasma generation unit, and the plasma generation unit excites the first gas into plasma and supplies the first gas to the substrate in the chamber;
• and
• a second film forming step in which the first gas supply unit supplies an organic metal gas containing the group III element to the substrate in the chamber, the second gas supply unit supplies a second gas not containing hydrogen and containing nitrogen gas to the plasma generation unit, and the plasma generation unit excites the second gas into plasma and supplies the second gas to the substrate in the chamber.