sputterdeposition

Sputter deposition, or sputtering, is a physical vapor deposition method for making thin films by ejecting material from a solid target onto a substrate.

In a typical setup, a vacuum chamber houses a target and substrates. A plasma, usually argon, is generated by applying a high voltage. Argon ions bombard the target, ejecting atoms that travel to and coat the substrate. Magnetron sputtering uses magnetic fields to increase plasma density and deposition rate.

Reactive sputtering introduces gases such as oxygen or nitrogen to form compounds in situ (for example TiN or Al2O3). Cosputtering combines multiple targets to create alloys or composite films.

Key parameters are pressure, power, substrate temperature, target–substrate distance, and gas composition. Substrate bias can affect film density and mechanical stress.

Films can be metals, nitrides, oxides, carbides, or polymers. Properties such as thickness, density, adhesion, and microstructure depend on the energy of arriving species and the thermal budget during deposition.

Advantages include dense, adherent films and good conformity to complex shapes, along with broad material compatibility at relatively low substrate temperatures. Limitations include equipment cost, target poisoning in reactive sputtering, and residual film stress.

Applications span electronics (interconnects and barriers), optics coatings, and protective or hard coatings (such as TiN), as well as MEMS and solar devices.

Historical notes: sputtering emerged in the 1960s as a practical deposition method; magnetron sputtering was introduced in the 1970s and significantly improved deposition rates and film quality.