The vacuum arc plasma source and its applications

Summary form only given. A vacuum arc is a gas discharge that maintains itself by providing the conductive medium between cathode and anode through evaporation of material from either one of the electrodes. The rather rapid material evaporation process occurs in microscopic spots on the electrode surface. The spot´s existence is highly dynamic and determined by the interaction between the surface near solid-state region of the electrode and the generated plasma in front of it. The material leaves the electrode region fully ionized and expands into the vacuum chamber with energies in the range of several tens of electron volts. This expanding plasma can be utilized e.g. for surface treatments by exposing a substrate to it. The phenomenon of the vacuum arc has been researched for more than a hundred years and the vacuum arc has meanwhile become a state-of-the-art plasma source for thin film deposition and plasma surface treatment applications. The paper gives an overview of the vacuum arc phenomenon and discusses basic discharge parameters for typical materials. Practical implementations of dc and pulsed discharges are introduced and compared with respect to current and future applications.