THE SI P-PARTIAL DENSITY OF STATES IN SINX (0-LESS-THAN-X-LESS-THAN-2.0)

Some properties of non-stoichiometric amorphous silicon nitride, SiN(x) (0 < x < 2.0), prepared by physical vapour deposition in which hydrogen was excluded from the process, were investigated by X-ray fluorescence spectroscopy. The Si K(beta) and Si K(alpha) emission lines were measured. A non-bonding p-type vacancy state on the top of the upper Si valence band is identified up to the composition x = 1.2. This state was not observed in other studies of hydrogenated SiN(x):H systems. The N2s state derived lower valence band was split from the upper valence band with 2 eV valence band gap. The observed non-linear dependence of the Si p-band on x is inconsistent with a two-phase (Si and Si3N4) linear superposition model of this semiconducting amorphous alloy. The random bonding model is consistent with this dependence.