Effect of deposition flux on surface roughness of LiNbO3 thin film grown on sapphire substrate by pulsed laser deposition

The variation of surface morphology and roughness of LiNbO3 film on sapphire substrate with deposition flux was investigated. The film deposition was carried out by pulsed laser deposition (PLD) and then flux was controlled with frequency of pulsed laser. With increasing the deposition flux, that is the frequency of laser pulse, the film surface became smoother and thus the surface flatness was improved. In case of the frequency of 15 Hz, the rms roughness of the film surface was constrained below 2.0 nm even at the film thickness of about 300 nm.