Cathodic arc deposition

The arc evaporation process begins with the striking of a high current, low voltage arc on the surface of a cathode (known as the target) that gives rise to a small (usually a few micrometres wide), highly energetic emitting area known as a cathode spot.

The cathode spot is only active for a short period of time, then it self-extinguishes and re-ignites in a new area close to the previous crater.

If a reactive gas is introduced during the evaporation process, dissociation, ionization and excitation can occur during interaction with the ion flux and a compound film will be deposited.

By not allowing the cathode spot to remain in one position too long aluminium targets can be used and the number of droplets is reduced.

Arc spots are generated by a mechanical trigger (or igniter) striking on the open end of the target making a temporary short circuit between the cathode and anode.

The plasma beam from a Cathodic Arc source contains some larger clusters of atoms or molecules (so called macro-particles), which prevent it from being useful for some applications without some kind of filtering.

Cathodic arc deposition is actively used to synthesize extremely hard films to protect the surface of cutting tools and extend their life significantly.