In addition to the application of the coatings, the following issues should be considered when choosing the right targets:
◆ It should have good mechanical strength and chemical stability after film formation.
◆ It should have good bonding force with the substrate after the target film is formed. Otherwise, a film material with good adhesion to the substrate should be used. At first, a layer of the bottom film is sputtered and then the desired film layer is deposited.
◆ Film materials that used for reaction sputtering film must be easily reacted with the reactive gas to form compound films.
◆ Under the premise of satisfying the coating performance requirements, the smaller the difference between the thermal expansion coefficient of the target and the substrate, the better. So as to reduce the influence of the thermal stress
◆ The selected target must meet the technical requirements of purity, impurity content, component uniformity, machining accuracy and so on.