Growth mechanism of Al₂O₃ film on an organic layer in plasma-enhanced atomic layer deposition

Differences in the physical and chemical properties of Al₂O₃ films on a Si wafer and a C_xH_y layer were investigated in the case of plasma-enhanced atomic layer deposition. The Al₂O₃ film on the Si had a sharper interface and lower thickness than the Al₂O₃ film on the C_xH_y. The amount of carbon-impurity near the interface was larger for Al₂O₃ on the C_xH_y than for Al₂O₃ on the Si. In order to understand these differences, the concentrations of Al, O, C, and Si atoms through the Al₂O₃ films were evaluated by using x-ray photoelectron spectroscopy (XPS) depth profiling. The emission intensities of CO molecule were analyzed for different numbers of deposition cycles, by using time-resolved optical emission spectroscopy (OES). Finally, a growth mechanism for Al₂O₃ on an organic layer was proposed, based on the XPS and OES results for the Si wafer and the C_xH_y layer. (paper)