Organosilicon plasma deposited polymers are of interest for different kinds of applications like packaging, passivation and dielectric layers. A large set of plasma processes is possible, among which are low-pressure plasma enhanced chemical vapour deposition (PECVD) and plasma assisted chemical vapour deposition (PACVD) often used. In this work, we studied the composition and surface morphology of the hexamethyldisiloxane (HMDSO) and tetramethyldisiloxane (TMDSO) layers produced by PECVD and PACVD deposition using three plasma generation processes (plasma reactors): RF inductively coupled plasma (RFICP), microwave distributed electron cyclotron resonance plasma (DECR) and microwave induced remote nitrogen afterglow (MIRA). The layer composition was investigated by Rutherford backscattering spectrometry (RBS) and by elastic recoil detection analysis (ERDA) and the layer surface morphology was determined by atomic force microscopy (AFM). Composition, density and morphology (roughness, porosity) of the layers is discussed in connection with deposition techniques used.