Fundamentals of vacuum physics

Because ion plating technology is applied mainly in low-pressure gas discharge, it may be helpful first to introduce the fundamentals of vacuum physics related to low pressure. Therefore this chapter consists of the following parts: the concept of vacuum, the movement rule of gas molecules in a vacuum environment, the interaction between gas molecules and solid surfaces, and the electron emission on the cathode surface. The critical parts are the energy exchange of collisions between gas molecules, the rule of electron overflow at the interface of solid and vacuum, the characteristics of thermionic emission and cold field emission, and the characteristics of secondary electron emission by electron bombardment and ion bombardment of the metal surface.