Vacuum arc evaporators in modern ion-plasma technology — D. Dukhopelnikov
1 Nov 2012
Dmitry Dukhopelnikov, Ph.D., associate professor, the head of laboratory “Technology of plasma coatings and plasma sources”
The arc discharge has been investigated since last two centuries, but nevertheless it is still considered as one of the most mysterious types of a gas discharge. Arcs are characterized by enormously high currents and glow intensities, and therefore are broadly used for metal welding and melting, and as powerful light sources.The so-called vacuum arc discharge with integrally cold cathode has been employed for thin film deposition. In vacuum arc evaporators, the discharge generates a flux of metallic plasma, which provides various types of metal and ceramic coating. The plasma composed of cathode atoms is practically fully ionized, which results in specific condensation processes developing in the ionic phase. Thus, further investigations of the vacuum arc discharge are largely stimulated by its high application potential for coating.
The method of vacuum arc evaporation, based on the cathode erosion occurring in the cathode spot, allows us to form different types of protective and decorative coatings as well as corrosion-, heat-, and wear-resistant coatings (including nanostructured coatings for instruments and turbine blades). The relative simplicity and low cost of the method made it possible to implement this technology for large-scale treatment (of large sheets of glass, metal, or plastic). Vacuum arc evaporators are used as sources of getter for high-vacuum gas-discharge pumps. The use of vacuum arc discharges is believed to be very promising for the synthesis of nano- and micropowder.
Although we have accumulated quite some knowledge about the physics of vacuum arc, many phenomena observed in the discharge still need to be understood. For instance, this type of arc is characterized by unusual behavior of the discharge column upon interaction with the magnetic field, and the emission and erosion processes at the cathode are poorly understood. Nevertheless, the vacuum arc discharge has been extensively employed for ion-plasma technology. Based on empirical knowledge, one can design the motion of the cathode spot, tune the erosion composition, and control the condensation processes at the treated surface.
Further advances in investigating the physics and technology of the vacuum arc discharge and evaporation will open up fascinating perspectives for major development in mechanical engineering, microelectronics, and nanotechnology. In this lecture I will address principal characteristics of the vacuum arc discharges and their applications in the modern ion-plasma technology.