In coating technology, the term "sputtering" refers to the removal of particles (atoms, ions or molecules) from a solid target by ion bombardment.

For this purpose, ions are typically generated from a gas and accelerated towards the target. There they collide with the atoms of the target. The original ions, as well as the disturbed particles, move through the material and collide with other atoms. Most of the ions and hit atoms remain in the material, but a small part of the atoms is scattered towards the surface by this process. Some of these particles leave the target and move towards the substrate to condense there as a layer.

In magnetron sputtering, the necessary ions are generated by a gas discharge that burns directly in front of the target. This can be excited, for example, by applying an electrical DC voltage or an AC voltage (DC sputtering or RF sputtering). In the case of DC excitation, the target consists of a slice of high-purity metal, for example titanium. In the case of RF sputtering, however, dielectric targets such as titanium oxide can also be used. If a reactive gas such as oxygen is added to the gas discharge, this leads to the formation of chemical reaction products such as oxides.

Due to the comparatively high kinetic energies (Ek∼10 eV) of the layer-forming particles, sputtered layers exhibit an amorphous microstructure and a high packing density (almost that of the solid).

The thermal load on the substrates during coating is lower than with conventional vapour deposition.