Deposition of noble metal contacts on YBa/sub 2/Cu/sub 3/O/sub 7-x/ thin films

摘要

Ohmic contacts with low specific contact resistivities between YBa/sub 2/Cu/sub 3/O/sub 7-x/ thin films and noble metals have been fabricated using ion beam sputter etching and RF-plasma contact preparation. The influence of deposition parameters has been investigated. Specific contact resistivities in the 10/sup -8/ Omega -cm/sup 2/ range at 77 K have been achieved and were evaluated using cross bridge Kelvin test structures with sizes varying between 5 and 50 mu m. The failure rate of wires bonded onto high-temperature superconductor (HTSC)-Au/Ag pads was unacceptable in most cases. Substantial improvements have been achieved with Cr/Ti adhesion sublayers. Deposition parameters for optimum pull test results on MgO and LaAlO/sub 3/ substrates are presented.