AlGaN/GaN HEMTs With Damage-Free Neutral Beam Etched Gate Recess for High-Performance Millimeter-Wave Applications

Abstract

The electrical performances of gate-recessed AlGaN/GaN high-electron mobility transistors (HEMTs) fabricated using the damage-free neutral beam etching (NBE) method are demonstrated. The NBE method could eliminate the plasma-induced defects generated by irradiating ultraviolet/VUV photons in the conventional inductively coupled plasma reactive ion etching method. The AlGaN/GaN HEMT device fabricated using the new gate recess process exhibited superior electrical performances, including a maximum drain current density ( ${I}_{\mathrm {DS,max}}$ ) of 1.54 A/mm, low $1/f$ noise, a current-gain cutoff frequency ( ${f}_{\mathrm {T}}$ ) of 153 GHz, a maximum frequency of oscillation ( ${f}_{\mathrm {{MAX}}}$ ) of 167 GHz, and a minimum noise figure (NF $_{\mathrm {{min}}}$ ) of 3.28 dB with an associated gain ( ${G}_{\mathrm {{AS}}}$ ) of 5.06 dB at 54 GHz. Such superior characteristics confirm the inherent advantages of adopting the damage-free NBE process in fabricating GaN devices for millimeter-wave applications.