Composition, stability and oxygen transport in lanthanum and hafnium aluminates thin films on Si

La and Hf aluminates are promising candidates to replace SiO2 as gate dielectric for future Si-based metal–oxide–semiconductor devices. In this study, ion beam analyses were employed to investigate the composition of La and Hf aluminate thin films deposited on Si and the modifications caused in these structures by annealing in low-pressure oxygen atmosphere. Complementary analyses were performed by electrical characterization of metal–oxides–semiconductor capacitors. Results are discussed in terms of oxygen diffusion, substrate Si oxidation and healing of O-deficient sites during annealing in O2.