title: Dislocation-pipe diffusion in nitride superlattices observed in direct atomic resolution.
abstract: Device failure from diffusion short circuits in microelectronic components occurs via thermally induced migration of atoms along high-diffusivity paths: dislocations, grain boundaries, and free surfaces. Even well-annealed single-grain metallic films contain dislocation densities of about 1014m-2; hence dislocation-pipe diffusion (DPD) becomes a major contribution at working temperatures. While its theoretical concept was established already in the 1950s and its contribution is commonly measured using indirect tracer, spectroscopy, or electrical methods, no direct observation of DPD at the atomic level has been reported. We present atomically-resolved electron microscopy images of the onset and progression of diffusion along threading dislocations in sequentially annealed nitride metal/semiconductor superlattices, and show that this type of diffusion can be independent of concentration gradients in the system but governed by the reduction of strain fields in the lattice.
authors.affiliation: Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Garbrecht
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.
authors.forename: Bivas
authors.initials: B
authors.lastname: Saha
authors.affiliation: Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Jeremy L
authors.initials: JL
authors.lastname: Schroeder
authors.affiliation: Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Hultman
authors.affiliation: Bradley Department of Electrical and Computer Engineering and Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24061, USA.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Sands