Formation of Ni Schottky contact and quasi-vertical Schottky barrier diode on SnO2 thin film

In the past, forming a Schottky contact on SnO2 with metal has been a significant challenge due to the surface electron accumulation layer on the SnO2 surface. In this study, we report a steady and reproducible Schottky contact between the Ni and the SnO2 (101) planes. Furthermore, we evaluate a quasi-vertical SnO2 Schottky diode. High-quality Nb:SnO2 and SnO2 single-crystal films with (101) plane orientation were grown sequentially on r-sapphire substrates by radio frequency magnetron sputtering in a mixed atmosphere of Ar and O2. By etching and liftoff, a Ni anode and an In cathode were deposited on SnO2 and Nb:SnO2, respectively, to make a Schottky diode. The diode has a Schottky barrier height of 0.64 eV and a specific on-resistance of 32 mΩ cm2, indicating good performance. X-ray photoelectron spectra reveal the upward band bending from bulk to surface of the (101) SnO2 film, which contributes to the formation of the Schottky contact with Ni.