Influence of post fabrication annealing on device performance of InAlN/ GaN high electron mobility transistors

In this study, effect of post-fabrication annealing (PFA) on the electrical performance of the InAlN/GaN high electron mobility transistors (HEMTs) has been investigated. With PFA, the gate Schottky barrier height increases by 94 % (from 1.03 eV to 2.00 eV) and the interface trap state density (D-it) is reduced by 27 %. Compared with the device without PFA, a higher on-current (11 %), a larger on/off current ratio (similar to 1 order), a higher transconductance (3 %), a reduced gate leakage current (84 %) and a lower subthreshold swing (10 %) are recorded in device with PFA. In addition, the improved electron mobility is observed and the reduction of polarization Coulomb field (PCF) scattering is proven in device with PFA due to the enhancement of polarization electrical field in InAlN/GaN heterostructure.