Préparation d'échantillons pour l'étude par GISAXS des mécanismes de déformation des matériaux par faisceaux d'ions lourds de haute énergie
The machanisms underlying structural deformations following swift heavy ion beam a-Si irradiation are subject of debate. We investigated the hypothesis of the presence of a liquid phase in the wake of the energetic ions in the thermal spike framework. a-Si samples were prepared in order to track a transient liquid phase by implanting Cu or Ag on the a-Si surface and exposing the sample to a 70 MeV Ag12+ beam. Cu and Ag are both very sensitive to segregation in Si and are therefore thought to be capable of keeping track of a molten transient state by concentrating on the ion track. Samples are to be investigated with GISAXS. Nanoscale implantation masks were developed from nanoporous alumina membranes in order to impose a pattern on the ion impact sites and thus improve GISAXS sensitivitity. An alignment method is also developed for the positioning of pores parallel to the ion beam direction. A nearly equidistant impact sites pattern was achieved by irradiating fused silica through these implantation masks.
Heavy ion thermal spike Structural deformation Segregation Phase transition Traces liquides Liquid track Alumine Alumina Anodisation Anodisation