Investigation of metal contacts to Nb-1.0 wt.%-doped SrTiO3

Au/Ag/Al/In contacts to Nb-1.0 wt.%-doped SrTiO3 (NSTO) were investigated. The contacts of the Au/Ag/Al electrodes which were grown by magnetic controlled sputtering techniques were not ohmic. After annealing at different temperatures in oxygen for 30 min, better Schottky barriers could be formed in the contacts of Ag/NSTO and Au/NSTO. However, the ohmic contacts of indium to rough surface of NSTO are easy to obtain by pressing, and that to the polished surface can be obtained by melting indium with high vacuum. The specific contact resistances for different metal contacts were measured, the ohmic contacts of indium to NSTO by the two method almost have the same specific contact resistance, which is approximately 8.0 × 10−7 Ω m2.