Radio frequency thermal plasma-processed Ni-W nanostructures for printable microcircuit electrodes

Abstract

Nonconventional alloy systems have been actively investigated to find an appropriate electrode candidate for highly integrated microcircuit applications. Here, a Ni-W nanoscale-alloy system is introduced to modulate the unwanted early densification of Ni nanoparticles by adopting a considerable amount of W in the single-step process of radio frequency thermal plasma synthesis. Multiple phases other than Ni phase, i.e., α-W and β-W, were found to coexist when the content of W was presumably beyond its solid solubility limit in Ni. Noticeable retardation of the densification of Ni was observed depending on the content of W in the resultant film electrodes fired at different temperatures up to 1200 °C. As expected, electrical resistivity of the film electrodes depended on the progress of densification. A large variation of electrical resistivity with different W contents was observed at the low temperature of 900 °C while the variation became very small at high temperatures of >1100 °C for all the films. The successful late densification indicates that the Ni-W alloy system is suitable as a microcircuit electrode with a reasonably low electrical resistivity of ~10−5 Ω cm.