Surface morphology and microstructure of Al-O alloys grown by ECR plasma deposition

摘要

The growth of polycrystalline and amorphous aluminum-oxygen alloy films using electron-beam evaporation of Al in the presence of an O(sub 2) electron-cyclotron-resonance (ECR) plasma was investigated for film compositions varying from 40% Al (Al(sub 2)O(sub 3)) to near 100% Al (AlO(sub x)). Processing parameters such as deposition temperature and ion energy were varied to study their effects on surface texture and film microstructure. The Al-rich films (AlO(sub x)) contain polycrystalline fcc Al grains with finely dispersed second-phase particles of (gamma)-Al(sub 2)O(sub 3) (1-2 nm in size). The surface roughness of these films was measured by atomic force microscopy and found to increase with sample bias and deposition temperature. Stoichiometric Al(sub 2)O(sub 3) films grown at 100(degrees)C and 400(degrees)C without an applied bias were amorphous, while an applied bias of -140 V formed a nanocrystalline (gamma)-Al(sub 2)O(sub 3) film at 400(degrees)C. The surface roughness of the Al(sub 2)O(sub 3) increased with temperature while ion irradiation produced a smoother surface.