The OES measurements were carried out in a wavelength range of 200-1100 nm using a Mechelle 900 spectrometer (Multichannel Instruments) with a cooled 12-bit CCD camera system. The emission spectrometer lens was positioned at the same axial height as the substrate table and at a radial distance of 85 mm from the substrate table and the photons were collected through an IR/UV transparent viewport. The emission spectra were collected during a continuous flow of precursors into a continuous plasma discharge. An exposure time of 0.1 s was used, the spectra were collected in continuous sampling, and the emission intensities from each frame were summed together.