What is the working principle of magnetron sputtering?

The working principle of magnetron sputtering is that electrons collide with argon atoms during the flying to the substrate under the action of electric field E, causing them to ionize to produce Ar positive ions and new electrons; new electrons fly to the substrate. The Ar ions accelerate to fly toward the cathode target under the action of an electric field, and bombard the target surface with high energy to cause the target to be sputtered. In the sputtered particles, a neutral target atom or molecule is deposited on the substrate to form a thin film, and the generated secondary electrons are subjected to an electric field and a magnetic field to generate a direction drift indicated by E (electric field) × B (magnetic field). E × B drift, its motion trajectory is similar to a cycloid.

In the case of a toroidal magnetic field, the electrons make a circular motion on the surface of the target in an approximately cycloidal form. Their path of motion is not only long, but also trapped in the plasma region near the surface of the target, and ionizes a large amount in this region. Ar bombards the target to achieve a high deposition rate. As the number of collisions increases, the energy of the secondary electrons is exhausted, gradually away from the target surface, and finally deposited on the substrate under the action of the electric field E. Since the energy of the electron is very low, the energy transferred to the substrate is small, resulting in a low temperature rise of the substrate.

The magnetron sputtering station is a collision process between incident particles and a target. The incident particle undergoes a complex scattering process in the target, collides with the target atom, and transmits part of the momentum to the target atom, which in turn collides with other target atoms to form a cascade process. During this cascade, certain target atoms near the surface gain sufficient momentum to move outward, and the target is sputtered out.