Abstract
The Nb surface effects on junction characteristics were investigated in Nb/oxide/Pb junctions in which the base electrode was cleaned by an Ar+CF4 mixture plasma. The oxide barrier was grown by rf plasma oxidation on polycrystalline and single-crystal Nb films (RRR=4-135). It was confirmed that Nb grain size affected Nb penetration depth, transition temperature, and junction gap structure. However, high junction quality (Vm> 30 mV) and high barrier height (φ∼1.0 eV) were obtained independent of the existence of Nb grain boundaries. Based on these results and previous XPS findings, that is, the formation of a thin Nb-F-O layer on a CF4 cleaned Nb surface, it is surmised that this thin layer deactivates the grain boundary region and reduces the problems associated with this region.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
