Magnetron sputtering is also a PVD process. Here, however, the material is not vaporized, but a so-called target (a solid plate of the desired coating material) is removed by high-energy particles. A plasma is generated in a vacuum chamber for this purpose. Positively charged argon ions from the plasma are strongly accelerated by an electric field at the target and collide with the target surface. This ion bombardment knocks atoms out of the target.
The magnetron considerably intensifies this process: strong magnetic fields are generated above the target, forcing the electrons in the plasma onto spiral paths. This keeps them close to the target for longer and leads to a higher ionization rate. The resulting denser plasma leads to a higher sputtering rate with lower energy consumption. The layers produced with magnetron sputtering are characterized by high density, homogeneity and excellent adhesion. They are often free of pores, evenly distributed over large areas and can be applied to complex geometries.