Method of manufacturing compound semiconductor device

A method of manufacturing a compound semiconductor device comprising the steps of:

• forming a first electrode of a capacitor and a gate electrode of a transistor on a compound semiconductor substrate via a first insulating film;
• forming a dielectric film of the capacitor on the first electrode;
• forming a second electrode of a capacitor on the dielectric film;
• forming a second insulating film having a hydrogen content which covers the second electrode, the dielectric film, and the first electrode;
• patterning the second insulating film by using a mask to leave the second insulating film covering directly an upper surface and both side surfaces of the second electrode to surround the second electrode with the dielectric film;
• and
• forming an insulating protective film which covers the second insulating film, the dielectric film, and the first electrode, and has a hydrogen content larger than that of the second insulating film.