Gold-free InAlN/GaN schottky Gate HEMT on Si(111) substrate with ZrO 2 Passivation

Abstract

The electrical properties of Ti/Al/Ni/W (25/200/50/100 nm) ohmic contact and Ni/W (350/50 nm) Schottky contact to InAlN/GaN HEMT grown on high resistive Si (111) substrate are reported in this study. The specific contact resistivity of Ti/Al/Ni/W contacts has been investigated as a function of annealing temperature and Ti/Al thickness ratio, and has achieved the lowest value of 1.06×10-6 Ω·cm2 after annealing at 900°C in vacuum. The maximum Schottky barrier height of the Ni/W (350/50 nm) contact achieved is 0.72 eV at room temperature. With ZrO2 passviation, the InAlN/GaN-on-Si HEMT exhibits a higher extrinsic transconductance of 160 mS/mm (by ∼33.3%) and a lower onresistance of 10 Ω/mm (by ∼16.7%) than that without passivation. © The Electrochemical Society.