Low-Resistance Ti/Au Ohmic Contact on (001) Plane Ga2O3 Crystal

We studied the Ti/Au Ohmic contact on (001) plane Ga2O3 single crystal wafer as a function of annealing temperature and crystallographic orientation. The lowest specific contact resistances of similar to 5 x 10(-4) Omega.cm(2) were obtained at 400 degrees C annealing temperature under nitrogen ambience. The Ohmic metal contact became degraded when annealed above 500 degrees C. The formation of Ti oxide might be responsible for the degradation of Ohmic contact at high annealing temperatures. In comparison with (010) Ga2O3 substrate, the Ohmic contact could be more easily formed on ((2) over bar 01) and (001) Ga2O3 planes, possibly due to high surface energy and dangling bond density. It is notable that the contact properties did not show any particular dependence on in-plane azimuth angles on (001) Ga2O3 substrate. (C) 2022 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.