The YBCO[001]/Ag interface: correlation between specific contact resistance and interfacial microstructure

The influence of the sample temperature during metallization on the electrical performance of silver contacts to c-axis oriented YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) thin films has been investigated. The specific contact resistance, /spl rho//sub c/, was measured for contacts of different lateral dimensions, prepared by in situ Ag deposition at different temperatures and defined by standard photolithography. When corrected for a non-uniform current distribution, this data shows that on average /spl rho//sub c/ is at least a factor 4 lower for contacts prepared by metallization on a heated (T/sub sub//spl ap/600/spl deg/C) YBCO surface than for contacts prepared by metallization at room temperature (RT). The improved electrical performance correlates with a distinct difference in the interfacial microstructure of similar contacts, previously observed with high-resolution transmission electron microscopy. >