Densification behavior and electrical properties of carbon nanotube-Ni nanocomposite films for co-fireable microcircuit electrodes

Nanocomposite thick-film electrodes are investigated for highly integrated microcircuit devices that require retarded densification in order to match potential co-fireable ceramic sheets. In this study, we introduce carbon nanotube (CNT) as an ingredient to retard the densification of the conducting Ni paste while minimizing the decrease in the electrical resistivity of the Ni paste. Well dispersed CNT/Ni pastes containing various amounts of CNT ranging from 1 to 5 wt% were screen-printed on a regular alumina substrate and fired at 800–1200 °C for 1 h in a reducing atmosphere. The retardation effect was evident even with 1 wt% CNT that exhibited late full densification at 1100 °C, which corresponds to the target firing temperature for ceramic sheets. Electrical resistivity was not significantly influenced by the low content of CNT, which corresponds to 3.39 × 10⁻⁵ Ω cm when compared to 2.97 × 10⁻⁵ Ω cm for pure Ni paste processed at the same temperature of 1100 °C. The results indicate that the Ni-CNT composite thick films are potentially useful as a competitive co-fireable electrode.