On the deposition process of silicon suboxides by a RF magnetron reactive sputtering in Ar–O2 mixtures: theoretical and experimental approach

Magnetron reactive sputtering of silicon oxides produced by Ar–O2 RF capacitive plasmas has been studied from a theoretical and experimental point of view. In this way a plasma model has been developed, that allows to know the densities of all the species in the discharge, as well as the flow of ions. This model is coupled with a sputtering model, which relates the plasma properties to the deposition process. Therefore, the substrate stoichiometry, as well as the deposition rate, is obtained as a function of the model input parameters, i.e. the argon and oxygen flows, RF power and pumping speed. These results are compared with experimental data on the deposited layers. The stoichiometry of the SiOx layers was determined by Rutherford backscattering spectroscopy and X-ray photoelectron spectroscopy measurements. A good agreement between theoretical predictions and experimental data is found in several deposition conditions. A discussion about these results is carried out.