12.5 Final.2025

In this study, the reduction of contact resistance (Rc) in RF GaN HEMTs with an 8 nm Al₀.₃₆Ga₀.₆₄N barrier layer was investigated using two approaches: Si implantation and recess etching. Employing the Si implantation method with an optimized dopant activation procedure reduced Rc by 70% down to approximately 0.17 Ω·mm. In comparison, a reference alloyed Ti/Al/Ni/Au ohmic contact scheme without implantation achieved an Rc of ~0.60 Ω·mm. For the same epitaxial layer design, utilizing the recess etching technique reduced Rc by 50% down to 0.25 Ω·mm.