MODULATED SPUTTERING PROCESS FOR SMOOTH SURFACE YBCO FILM DEPOSITION

A method to fabricate high T-c superconducting films exhibiting a smal l surface roughness has been developed, using conventional de inverted cylindrical magnetron sputtering. The method is based on the periodic modulation of the sputtering power during the deposition process; acc ordingly, deposition rate periodically reaches values as low as the 25 % of the full power value. YBCO films, fabricated following such a mod ulated deposition process, have been electrically characterized and st ructurally investigated by X-ray diffractometry. The surface morpholog y has been analyzed by atomic force and scanning electron microscopy. Surface roughness as low as 2 nm have been obtained by using a modulat ion period of 30 s.