AlGaN/GaN HEMT With 300-GHz fmax

Abstract

We report on a gate-recessed AlGaN/GaN high-electron mobility transistor (HEMT) on a SiC substrate with a record power-gain cutoff frequency (f[subscript max]). To achieve this high f[subscript max], we combined a low-damage gate-recess technology, scaled device geometry, and recessed source/drain ohmic contacts to simultaneously enable minimum short-channel effects (i.e., high output resistance R[subscript ds]) and very low parasitic resistances. A 60-nm-gate-length HEMT with recessed AlGaN barrier exhibited excellent R[subscript ds] of 95.7 ????mm, R[subscript on] of 1.1 ~ 1.2 ?? ?? mm, and f[subscript max] of 300 GHz, with a breakdown voltage of ~ 20 V. To the authors' knowledge, the obtained f[subscript max] is the highest reported to date for any nitride transistor. The accuracy of the f[subscript max] value is verified by small signal modeling based on carefully extracted S-parameters.