High Damage
Thin Film Coatings
Electron Beam
Deposition or e-beam deposition is a process used to coat optical
components (e.g. lenses, filters, crystals, etc.,) with
antireflection, high-reflection, scratch resistant, and other types
of coatings. This process uses an electron-beam gun to boil
electrons off of a heated cathode in order to melt the coating
material. After the coating material is melted it will then
evaporate on to the substrate (target material). This process takes
place within a de-pressurized vacuum coating chamber.
A coating
technique which is used to improve the structure density of
thin-film coatings by bombarding the growing film with accelerated
ions of oxygen and argon. The kinetic energy then dissipates in the
film, causing the condensed molecules to rearrange at greater
density.¹ This process takes place within a de-pressurized vacuum
coating chamber.
¹The Photonics
Dictionary. Book 4. “Ion-Assisted Deposition.” P. D-74. 2008
²
Photonics Dictionary. Book 4. “Sputtering.” P. D-137. 2008
³memsexchange,”Deposition Processes; Sputtering,” <http://www.memsnet.org/mems/processes/deposition.html>,2008
A vacuum
deposition method in which the coating material (target), is removed
from the surface of the coating source (cathode) by ion bombardment
and deposited upon substrates.²
Sputtering is a technology in which the material is released from
the source at much lower temperature than evaporation. The substrate
is placed in a vacuum chamber with the source material, named a
target, and an inert gas (such as argon) is introduced at low
pressure. A gas plasma is struck using an RF power source, causing
the gas to become ionized. The ions are accelerated towards the
surface of the target, causing atoms of the source material to break
off from the target in vapor form and condense on all surfaces
including the substrate. As for evaporation, the basic principle of
sputtering is the same for all sputtering technologies. The
differences typically relate to the manor in which the ion
bombardment of the target is realized. ³ This process takes
place within a de-pressurized vacuum coating chamber.