Stability of a current carrying single nanowire of tungsten (W) deposited by focused ion beam

作者：Mandal Pabitra^*; Das Bipul; Raychaudhuri A K

来源：Journal of Applied Physics, 2016, 119(8): 084301.

DOI：10.1063/1.4942164

We report an investigation on the stability of single W nanowire (NW) under direct current stressing. The NW of width approximate to 80 nm and thickness approximate to 100 nm was deposited on a SiO2/Si substrate by Focused Ion Beam (FIB) of Ga ions using W(CO)(6) as a precursor. Such nanowires, used as interconnects in nanoelectronics, contain C and Ga in addition to W. The stability studies, done for the first time in such FIB deposited NWs, show that under current stressing these NWs behave very differently from that observed in conventional metal NWs or interconnects. The failure of such FIB deposited NW occurs at a relatively low current density (similar to 10(11) A/m(2)) which is an order or more less than that seen in conventional metal NWs. The failure accompanies with formation of voids and hillocks, suggesting ionic migration as the cause of failure. However, the polarities of void and hillock formations are opposite to those observed in conventional metal interconnects. This observation along with preferential agglomeration of Ga ions in hillocks suggests that the ionic migration in such NWs is dominated by direct force as opposed to the migration driven by electron wind force in conventional metal interconnects.

• 出版日期2016-2-28