Magnetron sputtering

In all sputtering processes, material is removed from a source – the so-called “target” – by way of bombardment with heavy ions, often argon. This material can then be deposited on another material, the “substrate”. However, there are only a few of these ions in the normal state, as there are few particles in an artificial vacuum, i.e. a near-empty space. In addition to this, only a few of these particles are active as ions at room temperature. However, in order to remove a significant amount of material in a short time, we need more of these active ions.

In magnetron sputtering, permanent magnets are placed behind the target. The magnetic field forces electrons, i.e. negatively charged particles, to fly in spiral orbits.

This extends the time in which they can convert argon atoms into ions. These generated argon ions then move directly to the target and ensure that material is removed. The strong effect created by the magnetic field is recognizable on used targets, where a clear depression forms, the so-called “sputter trench”.

Another advantage of magnetron sputtering is the ability to operate at very low pressure. This means that the particles hit the substrate almost directly and without much deflection. This creates particularly dense coatings on the substrate.
 

Magnetron sputtering offers several advantages over other thin film deposition techniques:

1. Increased separation rate: Due to the concentration of the plasma at the target, material is removed and deposited more quickly.
2. Improved coating quality: Controlling the plasma enables more even and denser coatings.
3. Increased material efficiency: Less material loss due to efficient target utilization.Longer target service life: Limited erosion by a concentrated magnetic field extends the service life accordingly.
4. Lower operating temperatures: Facilitates deposition at lower substrate temperature, ideal for temperature-sensitive materials.
5. Less contamination: The process in the vacuum chamber involving an inert gas results in high-purity coatings.

To summarize: magnetron sputtering offers an efficient and high-quality method for thin film deposition.