This work reports on the epitaxial growth of crystalline high-k Gd2O3 on Si (111) by Molecular Beam Epitaxy (MBE) for CMOS gate application. Epitaxial Gd2O3 films of different thicknesses have been deposited on Si (111) between 650°C~750°C. Electrical characterizations reveal that the sample grown at the optimal temperature (700°C) presents an equivalent oxide thickness (EOT) of 0.73nm with a leakage current density of 3.6×10-2 A/cm2 at |Vg-VFB|=1V. Different Post deposition Annealing (PDA) treatments have been performed for the samples grown under optimal condition. The Gd2O3 films exhibit good stability and the PDA process can effectively reduce the defect density in the oxide layer, which results in higher performances of the Gd2O3/Si (111) capacitor.

Amorphous LaAlO3 high-k oxide was grown in a molecular beam epitaxy reactor on p-Si(001) using a thin γ-Al2O3 epitaxied buffer layer. Interfaces were free of SiO2 or silicates and remained abrupt despite the high temperature used for annealing, as X-ray photoelectron spectroscopy showed. Electrical measurements performed on as-deposited samples revealed a dielectric constant value close to that of the bulk, small equivalent oxide thickness and low density of interface states. But some negative charges were present, leading to a flat band voltage shift. Post deposition annealing with forming gas can correct this effect.