Formation of dust particles and related phenomena
Résumé
Formation of dust particles in a plasma can be the consequence of two mechanisms: the presence of reactive gases (for example silane, methane or acetylene), or the sputtering of surfaces exposed to the plasma. This sputtering induces the ejection from the surface of either small solid particles or molecules that behave like reactive gases in the plasma phase. Molecular precursors coming from reactive gases or sputtering thus initiate a complex succession of chemical and physical reactions, leading to the formation of dust particles. As they are growing, these dust particles usually acquire a negative charge proportional to their radius. If dust particle density is not negligible compared to the electron density, the plasma can be drastically affected by the presence of this new charged species that strongly reduces the free electron density sustaining the plasma. The plasma equilibrium can be disturbed and several types of unstable phenomena can be induced.