Substrate & target material

In the vacuum coating process, the material to be coated is called the substrate; the component material of the film is called the target. The substrate and target are in the same vacuum chamber. Atoms of the target are transferred and deposited onto the substrate by evaporation or by bombardment of the target with high-speed charged energy particles. Different functional membranes can be formed by replacing different targets.

PVD Vacuum Coating Material Requirements #

PVD requires the substrate to be electrically conductive (the outer surface can be insulating, but this affects the bonding). For example, ceramics cannot be a substrate, but enameled metals can be.

There are many types of targets, usually classified as arc targets and evaporation targets.

electric arc target #

Mainly used in decorative plating and tool hardcoat plating. The advantages of arc excitation are fast plating rates, high atomic dissociation rates, and high ionic energies, which enable direct reaction with gases to form Nitride, Carbide, Carbon Nitrdie, etc., which bond well with the metal substrate, e.g., TiN, TiC, TiCN. The thickness of the film is usually several um, which is one order of magnitude higher than that of sputtering. The film thickness is usually several um, which is an order of magnitude higher than that of sputtering. The disadvantage of arc excitation is the production of coarse droplets, which makes the film layer rough and dull, and also reduces the resistance to abrasion. The target material must be a good conductor, poor conductive materials can not be used as an arc target.

The arc target is usually round, 3"~6" in diameter, 30~50mm thick, molded in one piece without copper backing, with raised steps on the edge of the target surface to prevent the arc from escaping from the target surface, and locked onto the arc gun with screw teeth.

sputtering target #

Widely used in various optoelectronic and semiconductor industries. The sputtering layer is fine and smooth, the film thickness can be precisely controlled, good repeatability, and can be used as target material from conductor to insulator.

Sputtering targets are mainly round or square flat plates with a thickness of 3~15mm, with 6~10mm being the majority. The thickness of the sputtering target is much thinner than that of the arc target, in order to allow the magnetic field behind the target to penetrate to the front of the target to generate plasma. The stronger the magnetic field in front of the target, the stronger the plasma generated, which helps to increase the energy of the plasma and the dissociation rate of the target, thus improving the densification and adhesion of the film.