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DS: Dünne Schichten

DS 24: Poster presentation

DS 24.68: Poster

Dienstag, 28. März 2006, 15:00–17:30, P2

Characterization of 1/f-Noise during the Transition from Crystalline to the Amorphous State of the Binary Metal Alloy AuIn₂ by Ion Bombardment at Cryogenic Temperatures — •Moritz Trautvetter, Thomas Müller, and Paul Ziemann — Abteilung Festkörperphysik, Universität Ulm, D-89069 Ulm

Patterned polycrystalline AuIn₂ films (typical thickness 40 nm) were bombarded under cryogenic conditions (80 K) with 300 keV Argon and Helium ions. Under these conditions, the damage induced by the heavy Argon ions leads to complete amorphization of the film while for light Helium ions a defect rich but still polycrystalline state is obtained.

To characterize the 1/f-noise accompanying the ion induced stepwise amorphization, noise spectra are measured in situ at 80 K. For this purpose, a special type of correlation measurement technique is applied to detect the contribution of the 1/f-noise even below the thermal noise background. Further insight in what type of defects is causing the observed increase of the 1/f-noise due to ion irradiation can be obtained by combined annealing experiments, which reveal a significant reduction of the 1/f-noise whereas the accompanying resistance change is only small. In case of annealing the ion bombarded film at an elevated temperature close to crystallization, the previously ion induced 1/f-noise enhancement can be completely removed while the resistance of the still amorphous sample varies only by 2% due to this process.