Dust particles produced by Physical Enhanced Chemical Vapour Deposition (PECVD) in a capacitive discharge (13.56 MHz), can show a particular behaviour for specific discharge conditions and gas composition. Therefore, at a pressure of 120 Pa in a CH4-N2 mixture injected with a constant total gas flow rate of 5.6 sccm and a RF power of 80 W, the particles located above the grounded electrode have a periodical and vertical movement throughout the plasma bulk. This phenomenon only occurs for the following geometry of the grounded electrode: presence of through holes in the plate (used for particle collect) put on the grounded electrode.
The movement is linked to the competition between the forces acting on particles. Holes work as attractive poles and disturb the “classical” competition of forces, leading to the particle levitation in the cloud near the grounded electrode. We will discuss about the effect of the holes presence making the cloud above the grounded electrode moves vertically.
