Gallium-Enhanced Aluminum and Copper Electromigration Performance for Flexible Electronics

Abstract

Wide range binary and ternary thin film combinatorial libraries mixing Al, Cu, and Ga were screened for identifying alloys with enhanced ability to withstand electromigration. Bidimensional test wires were obtained by lithographically patterning the substrates before simultaneous vacuum co-deposition from independent sources. Current–voltage measurement automation allowed for high throughput experimentation, revealing the maximum current density and voltage at the electrical failure threshold for each alloy. The grain boundary dynamic during electromigration is attributed to the resultant between the force corresponding to the electron flux density and the one corresponding to the atomic concentration gradient perpendicular to the current flow direction. The screening identifies Al-8 at. % Ga and Cu-5 at. % Ga for replacing pure Al or Cu connecting lines in high current/power electronics. Both alloys were deposited on polyethylene naphthalate (PEN) flexible substrates. The film adhesion to PEN is enhanced by alloying Al or Cu with Ga. Electrical testing demonstrated that Al-8 at. % Ga is more suitable for conducting lines in flexible electronics, showing an almost 50% increase in electromigration suppression when compared to pure Al. Moreover, Cu-5 at. % Ga showed superior properties as compared to pure Cu on both SiO 2 and PEN substrates, where more than 100% increase in maximum current density was identified.

Minor Copper-Doped Aluminum Alloy Enabling Long-Lifetime Organic Light-Emitting Diodes

“…The lifetime enhancement may be attributed to the incorporation of copper that helped prevent the formation of high spikes during the deposition of the cathode and slow down the growth of the spikes during operation. The latter may be resulted from the mitigation of electromigration upon copper doping as revealed by the literature. − …”

Fabrication of the Silver Grids by Interfacial Interaction

“…[1] As a result, many materials such as conductive polymers, graphene, carbon nanotubes, metal oxides, and metals have been investigated as substitutes to ITO. [2][3][4][5][6][7][8][9][10][11][12][13] Unfortunately, most of them cannot manage the good balance between transmittance and conductivity. As an exception, Ag grids have been one of the most competitive alternatives to ITO with virtues as high transmittance, low haze, excellent conductivity, good mechanical properties, and low cost.…”