Damage-free cathode coating process for OLEDs

OLED displays require the growth of inorganic films over organic films. The inorganic film sometimes manifests as cathode metal (bottom-emission displays), or as the optical enhancement layer (OEL, in top emission displays). Sputtering is the first process of choice in both cases due to simplicity, low cost and scalability. However, plasma damage to the organic underlayers prevents sputtering from being routinely used. A closed-drift ion beam sputtering process was found effective in growing inorganic films with negligible damage to the organic underlayers.