Berlin 2012 – scientific programme
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DS: Fachverband Dünne Schichten
DS 38: Poster III: Resistive switching (jointly with DF, KR, HL); Thermoelectric materials (Focused session); Micro- and nanopatterning (jointly with O); Ion irradiation effects
DS 38.43: Poster
Thursday, March 29, 2012, 17:30–19:00, Poster E
Ion beam induced density changes and plastic phenomena — Tobias Steinbach, •Emanuel Schmidt, Aaron Reupert, Mathias Schmidt, and Werner Wesch — Institute of Solid State Physics, Friedrich Schiller University Jena
Conventional ion irradiation is a well-established standard doping method in semiconductor processing for effective modification of electrical, mechanical, optical and chemical properties. However, in the low energy range the ions are stopped mainly by elastic scattering with the lattice atoms, which results in the displacement of target atoms and consequently in lattice damage. This ion beam induced damaging and amorphization process is accompanied by three different radiation-induced deformation phenomena: densification, radiation enhanced viscous flow and anisotropic deformation. The change of stress associated with these effects can be investigated during irradiation by observing the bending of freestanding thin crystalline samples by means of an in situ scanning laser reflection technique, which was recently established at the FSU Jena. We present ion beam induced stress evolution as a function of fluence for the irradiation of semiconductors (Ge and Si) as well as for insulators (LiNbO3). In case of Ge and Si, the formation and relaxation of stress will be discussed as a function of fluence, nuclear energy deposition, projected ion range and irradiation temperature. In addition, the significant stress increase during beam interruption will be explained. In LiNbO3, the observed stress evolution depends on the crystallographic orientation and will be discussed based on the preferential rearrangement of displaced lattice atoms.