Influence of Fluorine-Based Dry Etching on Electrical Parameters of AlGaN/GaN-on-Si High Electron Mobility Transistors

The fluorine-based dry etching process is extensively employed in the fabrication of GaN-based High Electron Mobility Transistors. This research activity aims to the identification of the SF6 ICP etching process effects on the performances of depletion-mode AlGaN/GaN-on-Si HEMTs. By means of reverse-bias step-stress and time-resolved constant-stress, it has been observed (i) a short-term instability of both threshold voltage and gate leakage current under low reverse bias conditions, likely related to the permanent modification of electrical configuration of the Fluorine ions implanted within the epitaxial structure during the etching process; and (ii) that the introduction of the annealing phase mitigates the described instability.