Hollow cathode glow discharge is a special form of low-pressure glow discharge. Here the cathode assumes the shape of a hollow body, resulting in a much higher plasma density.
For many years, Fraunhofer IST has been examining the question of how this discharge type can be used in surface engineering. This has resulted in various plasma sources and corresponding processes with a broad range of potential applications. Among these, (hollow cathode) gas flow sputtering (GFS) is particularly noteworthy.
Gas flow sputtering (GFS) is a special PVD (physical vapour deposition) method among the sputtering processes. Unlike familiar magnetron sputtering however, the plasma is produced by a hollow cathode glow discharge and the transport of material is carried by an intense flow of argon gas. The (usually metallic) sputtering target takes the shape of a hollow cathode, generally in the form of two rectangular plates arranged in parallel or a short tube, with argon flowing through it. Ions from the hollow cathode discharge evaporate the target and the flow of argon transports the material to the substrate, primarily in atomic form. The typical working pressure is 0.2-0.8 mbar.