Magnetronsputtern

Magnetron sputtering (German: MagnetronSputtern) is a physical vapor deposition technique in which material is removed from a solid target by energetic ions generated in a plasma and subsequently deposited as a thin film on a substrate. A key feature is the use of a magnetron: magnets positioned behind the target create a magnetic field that traps electrons near the target surface, increasing plasma density and the ion flux toward the target. This enhances the sputtering rate and yields dense, well-adhered films at relatively low substrate temperatures.

In a typical system, the chamber is evacuated and filled with a rare gas such as argon. The target is biased with a DC or RF power supply to sustain a glow discharge. The sputtered atoms travel to the substrate and condense to form the coating. Conductive targets are commonly sputtered with DC magnetron; insulating or dielectric targets require RF magnetron or pulsed power to prevent charge buildup. Reactive sputtering uses reactive gases (oxygen, nitrogen) to form compound films such as oxides and nitrides.

Systems can be scaled from laboratory to industrial sizes. Common target materials include metals and alloys; in reactive sputtering, compounds like TiN, Al2O3, and Si3N4 can be produced. Substrate heating is often limited, but modest heating can improve film quality; additional biasing and ion-assisted deposition can enhance densification and adhesion.

Applications include hard coatings for tools and mechanical components, optical coatings (antireflection and reflective layers), decorative finishes, wear-resistant films, and protective coatings in semiconductor devices, solar cells, and MEMS.

Advantages include high deposition rates, dense and uniform films, good step coverage, and compatibility with large-area substrates. Challenges include target poisoning and arcing with reactive sputtering, residual stress in thick films, and the need for vacuum equipment and process control.