Improvement of Ohmic contacts on Ga2O3 through use of ITO-interlayers

The use of ITO interlayers between Ga2O3 and Ti/Au metallization is shown to produce Ohmic contacts after annealing in the range of 500-600 degrees C. Without the ITO, similar anneals do not lead to linear current-voltage characteristics. Transmission line measurements were used to extract the specific contact resistance of the Au/Ti/ITO/Ga2O3 stacks as a function of annealing temperature. Sheet, specific contact, and transfer resistances all decreased sharply from as-deposited values with annealing. The minimum transfer resistance and specific contact resistance of 0.60 Omega mm and 6.3 x 10(-5) Omega cm(2) were achieved after 600 degrees C annealing, respectively. The conduction band offset between ITO and Ga2O3 is 0.32 eV and is consistent with the improved electron transport across the heterointerface. (C) 2017 American Vacuum Society.