In this paper, AlGaN/GaN high electron mobility transistors (HEMTs) with etched-fin gate structures fabricated to improve device linearity for Ka-band application are reported. Within the proposed study of planar, one-etched-fin, four-etched-fin, and nine-etched-fin devices, which have 50-μm, 25-μm, 10-μm, and 5-μm partial gate widths, respectively, the four-etched-fin gate AlGaN/GaN HEMT devices have demonstrated optimized device linearity with respect to the extrinsic transconductance (Gm) value, the output third order intercept point (OIP3), and the third-order intermodulation output power (IMD3) level. The IMD3 is improved by 7 dB at 30 GHz for the 4 × 50 μm HEMT device. The OIP3 is found to reach a maximum value of 36.43 dBm with the four-etched-fin device, which exhibits high potential for the advancement of wireless power amplifier components for Ka band applications.
Keywords: AlGaN/GaN HEMTs; Ka band; SiC substrate; etched-fin gate structure; linearity.