Enhancement-Mode AlGaN/GaN HEMTs Fabricated by Standard Fluorine Ion Implantation with a Si3N4 Energy-Absorbing Layer

This paper presents a fabrication technology of enhancement-mode AlGaN/GaN high electron mobility transistors (HEMTs) using standard fluorine ion implantation. An 80 nm silicon nitride layer was deposited on the AlGaN as an energy-absorbing layer that slows down the high energy (∼25 keV) fluorine ions so that majority of the fluorine ions are incorporated in the AlGaN barrier. The threshold voltage was successfully shifted from −1.9 to +1.8 V, converting depletion mode HEMTs to enhancement-mode ones. The fluorine ion distribution profile was confirmed by Secondary Ion Mass Spectrometry (SIMS).