Nb/Nb oxide/Pb Josephson Tunnel Junctions Fabricated Using CF4 Cleaning Process

Publisher Website
Google Scholar
Abstract
Effects of an Ar and CF4 RF plasma mixture, in which the base electrode surface was cleaned prior to oxide barrier formation, on Nb/Nb oxide/Pb Josephson tunnel junction characteristics have been investigated. Good quality junctions with less leakage current (Vm=39.3 mV) and no knee at voltages just above the gap voltage have been obtained using the CF4 cleaning process (CFCP). It is speculated that the chemical etching reaction and a carbon layer generated on the cleaned Nb surface by CF4 plasma play an important role in achieving a cleaned based electrode surface free from damage and the formation of a good quality oxide tunnel barrier, respectively.