Disorder–Order Transition in Ga2O3 and Its Solid Solution with In2O3 upon Thermal Annealing

Abstract

The local ordering in amorphous Ga2O3 and (In x Ga1−x )2O3 thin films on Si(111) and its change on crystallization upon annealing are investigated. Synchrotron‐based extended X‐ray absorption fine structure data, as probed across the Ga K‐edge in conjunction with a numerical implementation of the scattering process including multiple scattering events, provide detailed insights into the bonding character of the Ga cations. Bond lengths and coordination numbers indicate the preferential formation of GaO4 tetrahedrons in the amorphous binary and ternary solid solution at the absence of long‐range ordering. Upon annealing there is no tendency toward the formation of long‐range ordering for the ternary alloy, while the amorphous Ga2O3 film turns into monoclinic β‐Ga2O3 crystallites with both tetra‐ and octahedral coordination.