The QCM sensor utilized gold coated AT-cut quartz crystals with an oscillation frequency of approximately 6 MHz. The frequency changes were monitored using an TFM260 Thin Film Monitor from BeamTec and analyzed using Inficon's SQM160 software, with a temporal resolution of one count per second. Details on how the QCM sensor was modified to be able to be biased for use in e-CVD has been described elsewhere. Optical emission spectroscopy (OES) measurements were performed over a wavelength range of 200-1100 nm using a Mechelle 900 spectrometer (Multichannel Instruments) equipped with a cooled 12-bit CCD camera system. The spectrometer lens was positioned at the same axial height as the substrate table and at a radial distance of 8.5 cm from it. Photons were collected through an IR/UV transparent viewport. The emission spectra were measured during the continuous flow of precursors into a steady plasma discharge. With an exposure time of 0.1 s, the spectra were collected via continuous sampling, and the emission intensities from each frame were summed together.