Fabrication of AlGaN/GaN high electron mobility transistors (HEMTs) on silicon substrate with slant field plates using deep-UV lithography featuring 5W/mm power density at X-band

In this work, AlGaN/GaN HEMTs on silicon with slant field plate have been successfully fabricated using deep-UV lithography. By using an angle exposure technique, submicron T-shaped gates with slant sidewalls were achieved. The 0.6 × 100μm² slant-field-plated AlGaN/GaN HEMT on silicon substrate exhibited a peak value of transconductance of 214 mS/mm and a breakdown voltage of 122 V. Through high-frequency measurements, the device revealed a current gain cutoff frequency (f_T) of 24 GHz, a maximum oscillation frequency (f_max) of 49 GHz and an output power density of 5.0 W/mm at X-band.