Spacer Side-wall Processed 0.15 μm GaN HEMT for Ka-band Application

In this paper, we have effectively demonstrated 150 nm-gate-length AlGaN/GaN high electron mobility transistors (HEMTs) on 4-inch SiC substrate. The 150 nm gate-length was accomplished by utilizing traditional I-line stepper photolithography, together with a nitride spacer side-wall. This method offers superior processing efficiency compared to E-beam lithography with high wafer uniformity. The devices processed with this spacer side-wall aided method demonstrated comparable electrical performances as that of E-beam processed one with f_T of 45 GHz, f_MAX of 80 GHz, Pout of 31 dBm and PAE of 45% at 29 GHz, which can be imported to large scale manufacturing.