Nitride-based high electron mobility transistor and manufacturing method thereof

A method of manufacturing a nitride-based high electron mobility transistor, comprising:

• preparing a substrate;
• forming a first semiconductor layer and a second semiconductor layer sequentially on the substrate;
• forming a source electrode and a drain electrode on the second semiconductor layer;
• depositing a first insulating film on the second semiconductor layer and at least partially on the source electrode and the drain electrode;
• forming an opening in the first insulating film between the source electrode and the drain electrode;
• forming a dielectric on the first insulating film to surround the opening of the first insulating film;
• depositing a second insulating film on an inner sidewall of the dielectric;
• and
• forming a gate electrode on the dielectric to fill the opening of the first insulating film and inside the inner sidewall of the dielectric,
• wherein the dielectric is formed such that a width of the inner sidewall at a bottom end of the dielectric is smaller than a width of the inner sidewall at a top end of the dielectric.