IAD is a variant of the electron-beam evaporation process which adds a high energy ion beam directed at the substrate to assist deposition process. The ions act almost like an atomic level hammer, producing a higher molecular packing density than can be achieved with purely by e-beam. The ion beam can also be used to pre-clean or etch the surface of the substrate, which can improve adhesions of the coating making it less susceptible to Laser Damage. The result of denser packing is increased durability to environmental or physical impacts as well as lower and shifting than films produced with non-IAD electron beam evaporation.
Plasma ion assisted deposition represents an evolution of the ion assisted e-beam process mentioned above, but with an extra boost. The PIAD process relies on electron beams to evaporate coating materials prior to deposition on the substrate as does ion assist process. The difference is the plasma assist process uses ionized reactive gases to promote the adhesion and improve the coating on a microstructure level as Unlike its predecessor, however, plasma assist combines the reactive ions and evaporated coating materials within a high-density DC plasma.
Cold plasma ion assisted deposition basically encompasses all the benefits of IAD and PIAD while adding the capability of cold ions. The cold or low temperature ions allow the overall process temperature to be kept much lower (~60~150°C) for coating of polymers and other temperature sensitive substrates. The cold process still has the high deposition energy allowing for dense packing that make multi-layer coatings possible on plastics where they generally are not available through e-beam evaporation.
