Comparison of DC Sputtering, Magnetron Sputtering and Sputtering Coating
Sputtering is one of the main technologies for the preparation of thin film materials
. It uses the ions generated by the ion source to accelerate the aggregation in vacuum, forming a high-speed ion beam flow, bombarding the solid surface, and the ion and the atoms on the solid surface exchange kinetic energy, so that the atoms on the solid surface are separated from the solid and deposited on the substrate surface. There are three sputtering technologies: DC sputtering, sputtering coating and DC magnetron sputtering.
DC sputtering means that the target material is installed on the cathode surface with glow discharge in the vacuum chamber and is bombarded by ions; the sample table with coated substrate or workpiece is installed and the vacuum chamber is grounded as the anode. During the operation, after the vacuum chamber is pumped to a high vacuum, argon is introduced, and the vacuum degree is maintained at about 1.0pa, plus 2-3kv DC voltage above the two electrodes, a glow discharge can be generated. At this time, a high density plasma region is formed near the target (cathode), that is, the negative glow region. The sputtering effect occurs when the ions in the region bombard the target under the acceleration of DC voltage. The atoms sputtered from the target surface are deposited on the substrate or workpiece to form a coating.
Sputtering coating is a technology that bombards the target surface with charged particles in vacuum to deposit the bombarded particles on the substrate. Usually, the incident ions are produced by glow discharge of low pressure inert gas. The cathode target is made of coating material
, the substrate is used as anode, and 0.1-10pa argon or other inert gas is introduced into the vacuum chamber to generate glow discharge under 1-3kv DC negative high voltage or 13.56MHz RF voltage of cathode (target). The ionized argon ions bombard the target surface, making the target atoms splash and deposit on the substrate, forming a thin film.
DC Magnetron Sputtering
In magnetron sputtering, because the moving electrons are subjected to Lorentz force in the magnetic field, their motion paths will bend or even spiral, and their motion paths will become longer, thus increasing the number of collisions with the working gas molecules, increasing the plasma density, so that the magnetron sputtering rate can be greatly improved, and they can work at a lower sputtering voltage and air pressure, reducing On the other hand, it also improves the energy of the atoms incident on the substrate surface, so it can improve the quality of the film to a great extent. At the same time, the electrons that lost energy after many collisions have become low energy electrons when they reach the anode, so that the substrate will not overheat. Therefore, magnetron sputtering has the advantages of "high speed" and "low temperature".
The disadvantage of this method is that the insulator film can not be prepared, and the inhomogeneous magnetic field used in the magnetic control electrode will cause significant inhomogeneous etching of the target, resulting in low utilization rate of the target, generally only 20% - 30%.