In the present work, a comparison between infrared spectroscopy (IR) and hydrogen forward scattering (HFS) results is presented. The hydrogen content has been calculated in terms of number of atoms/cm 3 using the Lanford and Rand absorption cross-section values, and as absolute atomic percentage. The total atomic density value has been evaluated from density measurements (relative error less than 4%) obtained by weighing the sample before and after the deposition. The relative error of the H content is less than 15% for IR measurements (calculated through the propagation law) and about 10% for HFS results. These two techniques have been found to be in good agreement within experimental errors. A second finding is that deposition temperature strongly influences the total H content while no significant dependence with rf power density and NH 3 /SiH 4 ratio has been observed. The NH 3 /SiH 4 ratio is strictly related to [Si-H] and [N-H] bond concentrations.