Accordingly, magnetic targets require a high strength magnet assembly in the sputtering gun. There are several reasons for this. A standard sputtering gun has a lower strength magnet assembly that will yield a maximum target life for non-magnetic materials. If you put magnetic targets in a standard sputter gun you should see, with a DC power supply, high voltage and no current – and thus no sputtering.
High strength magnet packs have been designed which are drop-in replacements for the conventional magnet designs. These higher strength magnet sets are capable of saturating the magnetic target and still have enough strength left to establish the electron trap over the target. As an example, a 2 inch diameter cathode, without target, outfitted with a standard pack has a surface magnetic field on the order of 1,000 gauss. The same cathode with a high strength magnetic pack has a surface field of roughly 2,000 gauss.
Also the thickness of magnetic targets must be tightly controlled as well. For instance, on a 2" sputtering gun with a high strength magnet assembly one can only run a .06" thick iron target, a .100" thick Co target, and a .125" thick Ni target. Anything thicker will shunt event the high strength magnet packs.
Category: Deposition Materials
Related Topics: Sputtering