| AVS 56th International Symposium & Exhibition | |
| Thin Film | Wednesday Sessions |
| Session TF-WeM |
| Session: | Nanostructuring Thin Films I |
| Presenter: | S. Seshabhattar, North Carolina State University |
| Authors: | S. Seshabhattar, North Carolina State University P.D. Rack, University of Tennessee R. Pearce, University of Tennessee D.K. Hensley, Oak Ridge National Laboratory M. Fuentes-Cabrera, Oak Ridge National Laboratory J.D. Fowlkes, Oak Ridge National Laboratory M.L. Simpson, Oak Ridge National Laboratory and University of Tennessee A.V. Melechko, North Carolina State University |
| Correspondent: | Click to Email |
Synthesis of nanoparticles research witnessed a remarkable headway with techniques spanning a wide range of materials and offering good control over particle shape and size. Top –down approaches have become successful in achieving controlled positioning of nanoparticles in pre-defined templates. A self-assembly method, however, is highly desirable because of its simplicity and compatibility with heterogeneous integration processes. Thin elemental or multicomponent films can be destabilized into self assembled arrays of nanoparticles. We will discuss how heating of ultrathin films can be a powerful but simple tool to fabricate functional nanostructures. Thin metal films on inert substrates are generally unstable, with their free energy resembling that of a spinodal system. Such films can spontaneously evolve into predictable morphologies with defined length scales. This process has been extensively used to prepare arrays of catalyst nanoparticles on Si surfaces for growth of vertically aligned carbon nanofibers. In this work we report on the behavior of Cu-Ni alloy thin films during solid state dewetting. The segregation of Cu-Ni alloy thin films during solid state destabilization on Si is in contrast to behavior expected from isomorphous system. Thin films of Cu-Ni and Ti-Cu-Ni were formed on Si and subjected to annealing temperatures from 300 o C - 700oC. Scanning Electron Microscopy(SEM) micrographs of these films revealed the formation of Cu-rich clusters on the surface prior to complete dewetting of the film in the range of temperatures much lower than dewetting of Ni film. The size and density of the Cu-rich regions increased with the increase in annealing temperatures. With increase in temperature the shape of these regions developed from irregular to cubical. The evolution of the alloy composition studied with Energy-Dispersive X-ray spectroscopy(EDX) mapping on both Si and Si covered with a Ti diffusion barrier will be presented. The solid state dewetting will be compared to laser processed films, that is, dewetting in a fluidic transport regime rather than diffusive transport regime.
This work was sponsored by the Materials Sciences and Engineering program of the DOE Office of Science.