Regensburg 2007 – scientific programme

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DS: Fachverband Dünne Schichten

DS 24: Ion Beam Techniques

DS 24.6: Talk

Thursday, March 29, 2007, 12:30–12:45, H34

Mechanical stress in low-energy ion-irradiated germanium: Experiments and simulations — •Tobias Edler and S.G. Mayr — I. Physikalisches Institut, Friedrich-Hund-Platz 1, Georg-August-Universität Göttingen, 37077 Göttingen, Germany

In the present contribution we focus on the origins and impacts of the swelling anomaly in amorphous germanium during ion bombardment. Experimentally, amorphous germanium thin films were grown from vapor, and subsequently bombarded with Ar⁺ ions with energies of up to 3 keV. Stress generation is monitored by a laser beams deflection method. In order to identify the underlying mechanisms of stress generation, molecular dynamics simulations were performed, in which crystalline and amorphous germanium films of different densities were irradiated.

We find a good agreement between experiments and simulations, which both clearly show the generation of compressive stresses, which saturate at 200 MPa. These stresses can be attributed to the generation of voids with sizes of approximately 1 nm several nanometers below the surface.

This work was financially supported by the DFG – SFB 602 TP B3.