Model for power coupled to RF planar magnetrons. Experimental validation and application to CNx thin film deposition

We focus here on the particular case of radio frequency (RF-13.56 MHz) planar magnetrons from fundamental point of view, which is supported by experiments. The description of the power coupled to the discharge through the plasma bulk electrons can be expressed as a sum of two terms. One can be related to the drift heating and the other one to the ohmic heating. The relative importance of these two terms gives a pressure interval for the normal operation of RF magnetrons, lying between 0.2 Pa and approximately 13 Pa. Radio frequency compensated Langmuir probe results are in good agreement with model predictions showing two distinct regimes. The normal one is the low pressure-high efficiency magnetron regime while the diffusion one is the high-pressure regime. Contrasting carbon nitride film properties are evidenced, when the discharge operates at normal or at high-pressure regimes. Proposed model can partially explain film features.