Fabrication of AlGaN/GaN HEMTs with slant field plates by using deep-UV lithography

In this work, AlGaN/GaN HEMTs 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 method is simple of cost effective. The 0.6 × 100μm
²
slant-field-plated AlGaN/GaN HEMT on silicon substrate exhibited a peak value of transconductance higher than 200 mS/mm and a breakdown voltage higher than 100 V. Through high-frequency measurements, the device revealed a current gain cut-off frequency (fT) of 24 GHz, a maximum oscillation frequency (fmax) of 49 GHz.