Deposition And Analysis Of ReBa₂Cu₃O_7-δ Thin Films

Fabricating high quality HTS thin film with high Tc is a key step for its application in micro-electronics devices. The growth orientation of YBa2Cu3O7-δ(YBCO) film can transit from c to a-axis after the film reaches a critical thickness, leading to an inverse dependency of the critical current density (Jc) on their thickness (dp): J c∝1/dp. Therefore, it is necessary to investigate how to avoid a-axis growth in thick films.In this work, we adopted a simply method to control the size of particulates landing on the substrate by changing the target. The target used for the deposition of the YBCO film was sintered at a temperature far below YBCO phase formation. Lower the sintering temperature, smaller the size of the particulates in the target. Thus, if the fine particulates land on the surface of c-axis oriented YBCO film, they can be easily rearranged into the YBCO film, and could not influence c-axis growth in the thick PLD films. Even when the thickness of the film reached to ~1μm, the c-axis orientation still remains.We successfully deposited epitaxial SmBa2Cu3O7-δ(SBCO) thin film at the substrate temperature of 800℃。The thin SBCO film is a suitable buffer layer for the further growth of YBCO films. We also studied the effect of annealing temperature on the preferred orientation of the as-grown films, and found that higher annealing temperature is conducive to the c-axis growth of films.