Microstructure, phase transition, and interfacial chemistry of Gd2O3/Si(111) grown by electron-beam physical vapor deposition

The effects of growth temperature, film thickness, and oxygen flux on the microstructure, phase transition, and interfacial chemistry of gadolinium oxide (Gd2O3) films grown on Si(111) substrates by electron-beam physical vapor deposition were investigated using a combination of transmission electron microscopy (TEM), electron diffraction, scanning TEM, x-ray energy dispersive spectrometry, and electron energy loss spectrometry. The authors find that a low growth temperature (250 °C) and a high oxygen flux (200 sccm) led to a small grain size and a high porosity of the Gd2O3 film. Lowering the oxygen flux to 50 sccm led to reduced film porosity, presumably due to the increased diffusion length of the Gd atoms on the surface. Increasing the growth temperature to 650 °C resulted in a film with large columnar grains and elongated pores at the grain boundaries. Thin films grown at 250 °C consisted of cubic Gd2O3, but thermodynamically less stable monoclinic phase formed as the film thickness increased. Loweri...