Structural investigation of Ge-Sb-Sn thin films using transmission electron microscopy

Atomistic structures of as-deposited and laser-induced-crystallized Ge-Sb-Sn layers have been examined using high-resolution electron microscopy (HREM) and nanobeam electron diffraction (NBED). Cross-sectional observations were performed on Ge-Sb-Sn thin films embedded in a multi-layered structure. Crystalline clusters were frequently observed in the HREM images of the as-deposited amorphous Ge-Sb-Sn thin film. Autocorrelation function analysis of the HREM image indicated a similarity between the structures of the crystalline clusters and that of rhombohedral Sb. Atomic pair-distribution functions obtained from the halo NBED intensity of the as-deposited amorphous Ge-Sb-Sn films also showed development of local structure whose atomic configuration is similar to that of the rhombohedral Sb. NBED revealed that the structure of the crystallized Ge-Sb-Sn thin film is also close to that of rhombohedral Sb. The atomistic structures of Ge-Sb-Sn thin films were compared with those of Ge-Sb-Te thin films and the rapid crystallization mechanism of these materials was discussed.