The Principle And Types Of The Vacuum Ion Coating

- May 25, 2018-

Ion plating is the use of gas discharge in the vacuum chamber or separation of the evaporated material portion, and the vaporized material or reactant is deposited on the substrate while the gas ions or the particles of the evaporated material are bombarded. The ion plating which combines the glow discharge phenomenon, plasma technology and vacuum evaporation not only significantly improve the film quality, but also expand the application of the film. Its advantages are strong film adhesion, good diffraction, and extensive film materials.

D.M. proposed the principle of ion plating for the first time. The working process is as follows: vacuum chamber is pumped to a vacuum degree of 4×10-3 Pa or higher first, then connect high voltage power supply, and a low-temperature plasma area of low-pressure gas discharge is established between the evaporation source and the substrate. The substrate electrode is connected to the 5 KV negative DC high voltages to form a glow discharge cathode. The inert gas ions generated in the glow discharge region enter the dark area of the cathode and accelerated by the electric field to bombard the surface of the substrate and cleaned. While the coating process, the target is heated to gasification and its atoms enter the plasma area, and collide with the inert gas ions and electrons, a few part of the ionization. After ionizing, the ions and gas ions bombarded the surface of the coating with higher energy, resulting in the improvement of film quality.

There are many kinds of ion plating, such as resistance heating, electron beam heating, plasma electron beam heating, high frequency induction heating, etc. There is a great difference between the multi arc ion plating and the general ion plating. The arc discharge is used in the multi arc ion plating, but it is not deposited by the glow discharge of the traditional ion plating. In a simple way, the principle of multi arc ion plating is to use the cathode target as the evaporation source, through the arc discharge between the target and the anode shell, so that the target is evaporated, thus the plasma is formed in the space, and the substrate is deposited. Therefore, different methods should be used for different ion plating.