Method for fabricating AIGaN/GaN-HEMT using selective regrowth

A method for fabricating an AlGaN/GaN-HEMT (High-Electron Mobility Transistor), comprising the steps of:

• preparing a semiconductor body including a substrate, and a stack of a buffer layer formed on the substrate, a UID-GaN layer overlying the buffer layer and a UID-AlGaN layer overlying the UID-GaN layer;
• forming a pattern of insulation film on a first principal surface provided by a surface of the UID-AlGaN layer;
• using the pattern of insulation film as a mask to regrow selectively an n+-GaN layer directly on a portion of a surface of the semiconductor body other than an area covered by the insulation film without etching the surface of the semiconductor body;
• defining, on the selectively regrown n+-GaN layer, a region reserved for an ohmic contact electrode to be formed, and forming the ohmic contact electrode on the region;
• and
• forming, within a region defining the patterned insulation film, an opening exposing a region reserved for a gate electrode to be formed, and forming the gate electrode on the region.