Thickness dependent electrical characteristics of InAlN/GaN-on-Si MOSHEMTs with Y2O3 gate dielectric and Au-free ohmic contact

Abstract

Thickness dependent electrical properties of Y2O3 gate dielectric based metal-oxide-semiconductor high electron mobility transistors (MOSHEMTs) on In0.18Al0.82N/GaN-on-Si are reported. A Au-free Ti/Al/Ni/W (25/200/40/50 nm) ohmic contact compatible for Si fab industry has been developed, which demonstrates a contact resistance of 0.56 Ω.mm and a specific contact resistivity of 1.45×10-6 Ω.cm2, obtained after annealing at 900°C in vacuum for 60 sec. A positive shift in threshold voltage with decreasing Y2O 3 film thickness is demonstrated while an improved MOSHEMTs transconductance and maximum saturation drain current have been obtained for thicker one. Besides, Y2O3 film thickness and annealing dependent interfacial properties have been investigated. © The Electrochemical Society.