(a) FTIR spectra of the thin films deposited for = 1, 5, 10 and 15 L min⁻¹ and Φ_HMDS = 500 µL min.⁻¹. Zoom was done in the 700 – 1700 cm⁻¹ range. (b) Evolution of the ellipsometry fit precision (R²)-from the fit regression considers a smooth and homogeneous silica-like layer, i.e. a single layer defined as a mixture of SiO₂ with void considering an Effective Medium Approximation (EMA) model- and AS₁ / SiCH₃ ratio as a function of the carrier gas flow rate for Φ_HMDS = 500 µL min.⁻¹. Silica-like and organosilicon range are depicted in white and grey respectively.