Angle-resolved photoelectron study on the structures of silicon nitride films and Si_3N_4/Si interfaces formed using nitrogen-hydrogen radicals

摘要

Soft x-ray-excited angle-resolved photoemission results for nitride films formed using nitrogen-hydrogen radicals on Si(100), Si(111), and Si(110) are reported. The data were obtained using synchrotron radiation, which allowed the Si 2p, N 1s, and O 1s levels to be investigated with the same probing depth. The following main results were obtained: (1) the Si_3N_4 film is covered with one monolayer of Si-(OH)_3N. Its areal density is 15% smaller on Si(111) than on Si(100) and Si (110), (2) the Si_3N_4/Si interfaces on all three surfaces are compositionally abrupt. This conclusion is based on the observation that no Si atoms bonded with three N atoms and one Si atom were detected, and (3) the observation that the number of Si-H bonds at the Si_3N_4/Si(110) interface is 38%-53% larger than those at the Si_3N_4/Si(100) and Si_3N_4/Si(111) interfaces indicates a dependence of the interface structure on the orientation of the substrate.