Mo ∕ Al ∕ Mo ∕ Au Ohmic contact scheme for AlxGa1−xN∕GaN high electron mobility transistors annealed at 500 °C

Low-resistance Ohmic contacts on Al0.3Ga0.7N∕GaN high electron mobility transistors (HEMTs) were formed with a Mo∕Al∕Mo∕Au metallization scheme which was annealed at a relatively low temperature of 500 °C. A contact resistance of 0.11±0.05Ωmm and a specific contact resistivity of 2.63×10−7Ωcm2 were achieved. This represents the best low-temperature-annealed Ohmic contacts on GaN-based HEMTs achieved to date.