Normally-off AlN/GaN HEMTs with a DIBL of 1.15 mV/V for RF Applications

In this work, normally-off, aluminium nitride (AlN)/gallium nitride (GaN) high electron mobility transistors (HEMTs) were successfully fabricated with T-gate structures. GaN HEMTs with AlN barriers and 70 nm T-gates exhibited +0.62 V of threshold voltage (V-th), 1.15 mV/V of drain induced barrier lowering (DIBL), and f(T)/f(max) of 89/232 GHz. This is a fundamental step towards realising W-band amplifiers for wireless communications applications.