Crystallography of excimer laser-crystallized In-Ga-Zn-O film

It is found by nanobeam electron diffraction that the excimer laser crystallization of In-Ga-Zn-O films which are not c-axis-aligned can lead to formation of polycrystalline In-Ga-Zn-O thin films having spinel structures. The crystal structure of ZnIn_xGa_2-xO₄ in which Ga site of ZnGa₂O₄ is substituted by In was obtained by first-principle calculation. It has been revealed that the unitcell constants and out-of-plane XRD peak angles (2θ) which are calculated from electron diffraction are reproduced in x = 0.5-1. In contrast, in the case of performing laser crystallization on a CAAC-IGZO film as a precursor, although polycrystalline In-Ga-Zn-O thin films having homologous structures are formed, formation of spinel structures is not observed.