Evaporating substances such as metals, compounds, etc. are placed in the crucible or hung on the hot wire as an evaporation source, and substrates to be plated such as metals, ceramics, plastics, etc. are placed in front of the crucible. After the system is pumped to a high vacuum, the material is evaporated by heating the crucible. The atoms or molecules of the evaporated material are deposited on the surface of the substrate in a condensed manner. Film thickness can range from hundreds of angstroms to several microns. The film thickness is determined by the evaporation rate and time of the evaporation source (or depending on the amount of charge) and is related to the distance between the source and the substrate. For large area coating, rotating substrate or multiple evaporation sources are often used to ensure the uniformity of the film thickness. The distance from the evaporation source to the substrate should be less than the mean free path of the vapor molecules in the residual gas so that vapor molecules do not collide with residual gas molecules to cause chemical reactions. The average kinetic energy of vapor molecules is about 0.1-0.2 electron volts.
Evaporating substances such as metals, compounds, etc. are placed in the crucible or hung on the hot wire as an evaporation source, and substrates to be plated such as metals, ceramics, plastics, etc. are placed in front of the crucible. After the system is pumped to a high vacuum, the material is evaporated by heating the crucible. The atoms or molecules of the evaporated material are deposited on the surface of the substrate in a condensed manner. Film thickness can range from hundreds of angstroms to several microns. The film thickness is determined by the evaporation rate and time of the evaporation source (or depending on the amount of charge) and is related to the distance between the source and the substrate. For large area coating, rotating substrate or multiple evaporation sources are often used to ensure the uniformity of the film thickness. The distance from the evaporation source to the substrate should be less than the mean free path of the vapor molecules in the residual gas so that vapor molecules do not collide with residual gas molecules to cause chemical reactions. The average kinetic energy of vapor molecules is about 0.1-0.2 electron volts.
There are three types of evaporation sources. (1) Resistance heating source: A refractory metal such as tungsten or tantalum is used to form a boat foil or a filament, which is heated by electric current, heated above it, or placed in a crucible (Figure 1 [Schematic diagram of evaporation coating equipment]). The source is mainly used to evaporate Cd, Pb, Ag, Al, Cu, Cr, Au, Ni and other materials. 2 High Frequency Induction Heating Source: Use high frequency induction current to heat helium and vaporized materials. 3 Electron beam heating source: Suitable for materials with high evaporation temperature (not less than 2000 [618-1]), that is, bombarding the material with electron beam to evaporate.