Low resistivity ohmic contacts on lightly doped n-type β-Ga2O3 using Mg/Au

Abstract

Mg/Au stacks were introduced to prepare ohmic contact at different annealing temperatures on Sn lightly doped β-Ga2O3. Linear current–voltage characteristics were realized when the annealing temperatures were 300, 400 and 500 °C. The transmission line measurements were used to extract the specific contact resistance (ρc) of the annealed samples. The ρc decreased as annealing temperature increased and a minimum ρc of 2.1 × 10−5 Ω cm2 was obtained for the sample annealed at 500 °C. However, the contact electrodes with the ρc of 1.3 × 10−4 Ω cm2 after annealing at 400 °C had better surface profile and stability. The ohmic contact mechanism and stability of electrodes were discussed in details.