Selectively area regrown III-nitride high electron mobility transistor

A method of forming a HEMT device on a plurality of thin film layers on a substrate, the method comprising:

• forming an ultra-thin barrier layer on the plurality of thin film layers, wherein the ultra-thin barrier layer has a barrier thickness of about 0.2 nm to about 20 nm;
• forming a dielectric thin film layer over a portion of the ultra-thin barrier layer to leave exposed areas of the ultra-thin barrier layer, wherein the dielectric thin film layer has a thickness of about 1 nm to about 100 nm;
• forming an SAG S-D thin film layer over the exposed areas of the ultra-thin barrier layer while leaving the dielectric thin film layer exposed, wherein the SAG S-D thin film layer has a thickness of about 3 nm to about 15 nm;
• removing the dielectric thin film layer to expose the underlying ultra-thin barrier layer;
• treating with fluorine the underlying ultra-thin barrier layer exposed by removal of the dielectric thin film layer to form a treated area;
• adding a source and drain on the SAG S-D thin film layer;
• depositing a dielectric coating over the ultra-thin barrier layer treated with fluorine such that the dielectric coating is positioned between the source and the drain;
• and
• positioning a gate electrode on the dielectric coating.