Epitaxial growth of Sc₂O₃ films on Gd₂O₃-buffered silicon substrates by Pulsed Laser Deposition

Full text: We aim at developing waveguide devices that can transform the performance of the gradient echo quantum memory based on bulk crystals. Essentially this requires thin crystalline films of rare-earth doped oxides with low levels of impurities and defects. We therefore investigated the optimal conditions to prepare high quality Sc₂O₃ films on Gd2O3-buffered silicon wafers using pulsed laser deposition technique since integration of the oxide on silicon will be compatible with standard semiconductor processing; the oxides have minimum lattice mismatching with silicon; there is a refractive index contrast between oxide and silicon in order to create the waveguide-based devices. Under the optimal conditions, X-ray θ-2θ scan of the film showed that, sharp oxide (222) peaks overlaid with silicon (222) and rocking curve of Sc₂O₃ (222) peak has a full width at half maximum(FWHM) of 0.10°. In-plain epitaxial relationship was confirmed by X-ray pole figure where Sc₂O₃ (111) is parallel to Silicon(111). High resolution Transmission electron microscopy images indicated clear interfaces and perfect lattice images with sharp electron diffraction dots. All these confirm that the oxide films we deposited on silicon are single crystalline with high quality. (author)