Ar dilution effects on hydrogen concentration and mass density obtained by X-ray and neutron reflectivity on hydrogenated amorphous nitride thin films

Neutron and X-ray reflectivity were used to determine the scattering length density profile of nitrogen-doped amorphous carbon (a-C:H:N) films perpendicular to their surface. By the combination of these two techniques, the mass density and the concentration of hydrogen were obtained. The influence of Ar plasma dilution on the properties of a-C:H:N films was studied as well. The observed differences suggest that as Ar is introduced into the gas mixture the mass density decreases. The hydrogen content for films grown in a N-2-rich plasma atmosphere is higher with respect to those obtained without nitrogen dilution; otherwise, At dilution promotes a lower hydrogen incorporation.