The device characteristics of Ir- and Ti-based Schottky gates AlSb/InAs high electron mobility transistors

• The InAs/AlSb HEMT using refractory iridium (Ir) gate technology was proposed.
• The Ir-gate exhibited a superior metal work function for increasing ΦB of InAs/AlSb heterostructures to 0.58 eV.
• The Ir-gate HEMT show higher threshold voltage and lower gate current.
• The Ir-gated HEMT also shows stability improvement of DC characteristics under hot carrier stress.

In this work, the InAs/AlSb high electron mobility transistors (HEMTs) on GaAs semi-insulating substrate using refractory iridium (Ir) gate technology was proposed. The Ir-gate exhibited a superior metal work function which was beneficial for increasing Schottky barrier height of InAs/AlSb heterostructures to 0.58 eV. Compared to the Ti-gate HEMT, the Ir-gate HEMT shows higher threshold voltage and lower gate leakage current owing to its higher Schottky barrier height and higher melting point. Moreover, the Ir-gated HEMT also shows the manifest stability improvement of DC characteristics under hot carrier stress as the Ti and As diffusion is alleviated.