Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 46: Magnetic Thin Films I
MA 46.12: Talk
Thursday, March 19, 2015, 18:00–18:15, H 1012
Fe3Si/Ge thin film stacks on GaAs(001) subtrates: An annealing study — •Jochen Kalt, Bernd Jenichen, and Jens Herfort — Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany
Multilayer stacks consisting of ferromagnetic metals and semiconductors are promising candidates for the realisation of spintronic device concepts. Implemantable structures feature highly orderd interfaces as well as semiconductor thin films of high crystal quality. Due to considerably different growth temperatures and chemical reactions at the interface, the overgrowth of a metal by a semiconductor requires sophisticated methods in order to achieve both of these features.
This report presents recent results in processing MBE grown Fe3Si/Ge thin film stacks with a post-growth in-situ annealing step. 9 nm of amorphous Germanium were grown at TG=150 ∘C on top of stochiometric Fe3Si/Ge on GaAs(001) subtrates. Subsequent annealing with temperatures ranging from 240 ∘C to 380 ∘C was done in order to crystallize the film, where the crystallisation process was in-situ monitored by RHEED. AFM measurements show an optimally smooth Germanium surface for an annealing temperature of TA=320 ∘C and an annealing time of 10 min. For TA≥330 ∘C rough surface structures emerge, while for TA≤330 ∘C rather smooth surfaces form, with thin bars dominating the surface morphology. XRR measurements reveal a high interface quality up to TA = 330 ∘C. XRD analysis indicates a new phase for TA≥330 ∘C, namely Fe3Si. Analysis of the in plane magnetic properties of the Fe3Si/Ge-layer shows that with increasing TA saturation magnetization and remanence decrease.