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DS: Dünne Schichten

DS 17: Ionenimplantation II

DS 17.8: Vortrag

Donnerstag, 27. März 2003, 12:00–12:15, GER/37

Self-organized restructuring of ceramic layers during irradiation with swift heavy ions. — •D. Etissa-Debissa¹, A. Feyh¹, B. Schattat¹, W. Bolse¹, and S. Klaumünzer² — ¹Institut für Strahlenphysik, Universität Stuttgart — ²Ionenstrahllabor, Hahn-Meitner-Institut, Berlin

After irradiation of thin NiO-layers on SiO₂ with high- energy ions at small angles of incidence we found that the layers reorganized into periodic lamellae, which are oriented perpendicular to the beam direction and have a height of about 1µm, a thickness of about 100 nm and an average distance of 1−3µm. This phenomenon is related to the mechanical stresses induced by the twofold phase transition between the solid and the liquid phase in the ion track. According to Grinfeld these almost uni-axial tensile stresses lead to a surface instability, which manifests itself in the formation of a periodic system of cracks perpendicular to the beam direction, extending from the surface to the SiO₂ substrate. With increasing ion fluence the material between the cracks shrinks along the beam direction and grows into height due to the so-called hammering effect, which finally results in the observed lamellae structure. In this contribution we will report on further experiments, in particular on the dependence of the structure of the lamellae on the initial NiO thickness. For comparison, additional experiments were carried out with other oxide-, nitride- and metal-coatings, which, except for ZnO, showed no effect or simple ripple formation.