
Once created, these high energy particles strike the surface of the target material. When they strike the target, these particles can be:
- reflected from the surface of the target
- penetrate into the target surface and disrupt the target material atoms
- free electrons from the target (called secondary electrons)
- eject material from the target, in which case the ejected material becomes the sputtered flux that is deposited
Requirements to sputter a material
- Vacuum chamber – low pressures are necessary to generate a plasma, allow effective transport of the sputtered material, and ensure purity of the film created.
- Power to the target – electricity is passed through the target to sustain the plasma and create the high-energy particles for sputtering.
- Cooling of the target – most of the power going through the target is converted to heat. The target must therefore be cooled or it will be damaged.
- Pure gases – either non-reactive gas (for example argon) or reactive gas (nitrogen or oxygen) is needed, depending on the process. Either way, the amount and flow of these gases are controlled very precisely.