NOVELTY - Plasma-assisted deposition for depositing at least one dielectric layer on a silicon-containing substrate (3), comprises (i) supplying at least one gas suitable for producing the dielectric layer into a separator (1), (ii) monitoring an emission intensity of the gas of at least one first wavelength or band, which is generated in the separator, (iii) generating a signal in response to the monitored emission intensity of the first wavelength or the band, (iv) transferring the signal to at least one control device (4), and (v) controlling at least one process parameter.    USE - The method is useful for manufacturing a solar cell (claimed).    ADVANTAGE - The method: is fast and economical; and enables improved monitoring of the deposition of dielectric layers.    DETAILED DESCRIPTION - Plasma-assisted deposition for depositing at least one dielectric layer on a silicon-containing substrate (3), comprises (i) supplying at least one gas suitable for producing the dielectric layer into a separator (1), (ii) monitoring an emission intensity of the gas of at least one first wavelength or band, which is generated in the separator, (iii) generating a signal in response to the monitored emission intensity of the first wavelength or the band, (iv) transferring the signal to at least one control device (4), and (v) controlling at least one process parameter influencing the deposition, and/or supplying the substrate into the separator by the control device, depending on the signal. INDEPENDENT CLAIMS are also included for:    (1) a solar cell-manufacturing method with the plasma-assisted deposition; and    (2) a device suitable for depositing the dielectric layer on the silicon-containing substrate, comprising (a) a separator for depositing at least one layer, (b) at least one supplying device (11) for supplying the gas suitable for producing the dielectric layer, (c) a moving device for supplying the substrate, (d) a monitoring device for monitoring the emission intensity of the first wavelength or band generated in the separator, (e) device for generating the signal in response to the monitored emission intensity of the first wavelength or band, and (f) at least one control device for controlling the process parameter influencing the deposition, and/or the supplying of the substrate to the separator.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of a control circuit.    Separator (1)    Substrate (3)    Control device (4)    Electronic controller (9)    Supplying device (11)