In situ studies of amorphization of the Ge-Al and Si-Al systems induced by 1 MeV electron irradiation

摘要

Ge/Al and Si/Al bilayer specimens, as well as Al-2.3 at. % Ge two-phase alloy specimens, were irradiated in situ with 1 MeV electrons at temperatures in the range 10--190 K in a high voltage electron microscope. At 10 K, it is found that for a Ge/Al bilayer specimen, amorphization at the interface occurs only when the Ge layer faces the incident electron beam, while for a Si/Al bilayer specimen amorphization occurs regardless of the direction of the incident beam. In this case, the critical fluence for amorphization ((Phi)(sub c)) to occur is (approx) 3 (times) 10(sup 23) cm(sup (minus)2) ((approx) 30,19 and 18 displacements per atom in Ge, Si and Al respectively). In the case of Al -- 2.3 at. % Ge alloy specimens irradiated at 10 and 50 K a crystalline-to-amorphous (c-to-a) transition is observed at (Phi)(sub c) (approx) 2.4 (times) 10(sup 23) cm(sup (minus)2) (24 and 14 dpa in Ge and Al respectively). The temperature dependence of (Phi)(sub c) is also studied for a Ge/Al bilayer specimen. The value of (Phi)(sub c) is a constant for T