Gold‐induced crystallization of amorphous germanium deposited on glass: Bilayer and multilayer films

Abstract

Gold‐induced crystallization (GIC) of amorphous germanium (a‐Ge) using bilayer and multilayer films was performed through electron beam evaporation on glass substrates. The GIC of a‐Ge was studied while the post‐annealing temperature was varied between 250 and 550 °C for a fixed annealing time. The structure of polycrystalline Ge films was investigated by employing X‐ray diffraction (XRD), Raman spectra and scanning electron microscopy (SEM). In both the bilayer and multilayer films the crystallization of a‐Ge took place from 250 °C. The amount of crystallization fractioning and film quality were improved as the annealing temperature increased. However, preferentially (220) oriented crystalline Ge was formed in the bilayer films, indicating a micro‐crystalline structure of the Ge. In the multilayer configuration (111) oriented crystalline Ge was observed indicating a poly‐crystalline structure of the Ge. Scanning electron microscopy (SEM) images clearly highlight the grain size difference between these structures, especially for annealing temperatures above 400 °C.