P.G. Ganesan, G. Cui, et al.
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
We demonstrate the use of polyallylamine hydrochloride (PAH)-polystyrene sulfonate (PSS) nanolayers to block Cu transport into silica. Cu/PSS-PAH/ SiO2 structures show fourfold enhancement in device failure times during bias thermal annealing at 200 °C at an applied electric field of 2 MV/cm, when compared with structures with pristine Cu-SiO2 interfaces. Although the bonding at both Cu-PSS and PAH-SiO2 interfaces are strong, the interfacial toughness measured by the four-point bend tests is ∼2 Jm-2. Spectroscopic analysis of fracture surfaces reveals that weak electrostatic bonding at the PSS-PAH interface is responsible for the low toughness. Similar behavior is observed for Cu-SiO2 interfaces modified with other polyelectrolyte bilayers that inhibit Cu diffusion. Thus, while strong bonding at Cu-barrier and barrier-dielectric interfaces may be sufficient for blocking copper transport across polyelectrolyte bilayers, strong interlayer molecular bonding is a necessary condition for interface toughening. These findings are of importance for harnessing MNLs for use in future device wiring applications. © 2007 American Institute of Physics.
P.G. Ganesan, G. Cui, et al.
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
X.-H. Liu, T.M. Shaw, et al.
ICEPT 2007
S. Malhotra, D. Canaperi, et al.
AMC 2004
D.D. Gandhi, B. Singh, et al.
Journal of Applied Physics