Amorphous to Polycrystalline Phase Transition in La₂O₃Films Grown on a Silicon Substrate Forming Si‐Doped La₂O₃Films

Abstract

Herein, La2O3 films are fabricated on a Si substrate without a La–Sr intermixing layer at the La2O3/Si interface using a pulsed laser deposition method. X‐ray diffraction data shows only two discernible peaks of the La2O3 films: hexagonal La2O3 (10‐1) and cubic La2O3 (222), indicating polycrystalline character. During film growth, the reflection high‐energy electron diffraction pattern from the La2O3 surface changes from an initial column shape to a complicated distributed dot pattern with narrow lines, suggesting possible structural property changes in the La2O3 film. The occurrence of a structural transition is confirmed by high‐resolution transmission electron microscopy (HRTEM), which exhibits a clear crystalline phase change from an initial ≈10 nm thick amorphous La2O3 film to polycrystalline La2O3 film on Si. Rutherford backscattering shows a reduced La–Si intermixing between La2O3 and Si. Furthermore, the results of X‐ray photoelectron spectroscopy atomic depth profile analysis show that observation of La‐silicate over the whole La2O3 film indicates that Si diffuses through whole thick La2O3 films forming Si‐doped La2O3 films. This study of the well‐defined structural characteristics and sharp interface of La2O3/Si will enable further understanding of high dielectric constant materials grown on Si by the introduction of advanced film growth technique.

Growth and Characterization of Lanthanum Germanide Thin Films by the Thermal Evaporation Technique

“…[ 1,2 ] These characteristics make them ideal candidates for various optoelectronic applications. [ 3 ] La‐based compounds are used in the production of transparent conductive films, which are essential for touchscreens, flat panel displays, and solar cells. [ 4,5 ] Their high transparency allows for efficient light transmission while the tunable conductivity enables electrical current flow.…”