ION-BEAM-ASSISTED DEPOSITION OF AL2O3 THIN-FILMS

The density, composition and microstructure of Al2O3 films grown by the ion-beam-assisted deposition (IBAD) technique were studied. This technique involves direct evaporation of Al2O3 by electron (e) beam while simultaneously bombarding with 300-500 eV O2+ ions. The arrival rates of ions and atoms were adjusted by varying the ion current and deposition rate respectively. The composition and density of the films were determined by a combination of Rutherford backscattering spectroscopy, thickness profilometry and cross-section transmission electron microscopy, while the microstructure was studied by plan-view transmission electron microscopy. The hydrogen content of the films was also analyzed using the proton recoil detection technique. IBAD of Al2O3 resulted in an amorphous phase with substrate at room temperature and a crystalline eta phase at a substrate temperature of about 600-degrees-C. The IBAD films at 600-degrees-C had bulk-like densities (about 3.7-3.9 cm-3) and they were free from pores. The stoichiometry of these films was about the same as the bulk stoichiometry. The IBAD film at 600-degrees-C contained a very small quantity of hydrogen atoms (about 1.48 x 10(21) cm-3) as compared with a regular e-beam-deposited film (about 4.4 x 10(22) cm-3).