Unbalanced Magnetron Sputter
A magnetron consists of a target with magnets arranged behind it to make a magnetic trap for charged particles, such as argon ions, in front of the target. When negative voltage is supplied to the target, argon ions are attracted to the target surface. Then atoms of the target are knocked out with mean kinetic energy-this is SPUTTERING. Secondary electrons are emitted from the target surface that become trapped by the magnetic fields and undergo further ionizing collisions sustaining the plasma. Confinement between a negatively biased target and closed magnetic field produces a dense plasma.