Ultraviolet-assisted pulsed laser deposition of thin oxide films

The properties of thin Y₂O₃, ZnO, and Ba_0.5Sr_0.5TiO₃ films grown using an in situ ultraviolet (UV)-assisted pulsed laser deposition (UVPLD) technique have been studied. With respect to films grown by conventional PLD under similar conditions but without UV illumination, the UVPLD grown films exhibited better structural, optical, and electrical properties, especially for lower substrate temperatures. These improvements can be explained by the combined action of several processes. First, high energy UV photons and ozone ensure a better in situ cleaning of the substrate prior to the deposition. Second, the presence of ozone and atomic oxygen formed by photodissociation of molecular O₂ promotes the growth of more oxygenated films. Finally, absorption of UV photons by adatoms could result in an increase of their surface mobility. All these factors have a beneficial effect upon crystalline growth.