Investigation of substrate temperature effect on the surface morphology of excimer laser deposited YBa2Cu3O7/CeO2 films on sa

摘要

Abstract: Excimer laser ablation is an excellent means of depositing high temperature superconducting (HTS) thin films because of high quality electrical properties of the resulting films and also because of the relative simplicity of the deposition system. The principal disadvantage of laser ablation is the contamination of the deposited film by particles, leading to a rough film surface. The influence of substrate temperature on surface morphology in YBa$-2$/Cu$-3$/O$-7$/ thin films deposited by excimer laser on r- plane sapphire with a CeO$-2$/ buffer layer has been investigated. The substrate temperature was measured using gold- nickel thermocouples on the substrate surface during deposition. The optimal deposition temperatures were found to be lower in comparison with films deposited on LaAlO$-3$/ because damage occurs to the buffer layer. Special attention was paid to the occurrence of droplets and outgrowths in the films. The ablation process produces droplets that range from 0.1 $mu@m to a maximum of 1 $mu@m in size. In the course of film growth these droplets undergo metamorphosis and form the basis of outgrowths. !8