300-GHz InAlN/GaN HEMTs With InGaN Back Barrier

This letter reports lattice-matched In0.17Al0.83N/GaN high-electron-mobility transistors on a SiC substrate with a record current gain cutoff frequency (f(T)) of 300 GHz. To suppress the short-channel effects (SCEs), an In0.15Ga0.85N back barrier is applied in an InAlN/GaN heterostructure for the first time. The GaN channel thickness is also scaled to 26 nm, which allows a good immunity to SCEs for gate lengths down to 70 nm even with a relatively thick top barrier (9.4-10.4 nm). In a 30-nm-gate-length device with an on-resistance (R-on) of 1.2 Omega . mm and an extrinsic transconductance (g(m.ext)) of 530 mS/mm, a peak fT of 300 GHz is achieved. An electron velocity of 1.37-1.45 x 10(7) cm/s is extracted by two different delay analysis methods.