Surface morphology, microstructure and electrical properties of Y-Ba-Cu-O thin films

The relationship between the surface morphology, the microstructure and the electrical properties of "in situ" YBCO thin films deposited by off- axis magnetron sputtering has been investigated in a wide range of deposition temperatures, deposition rate and pressure of gas mixtures. The Cu-rich surface particles formation observed in our experiment can be described using a classical thin film nucleation and growth model based on the concept of capture zones. The films with optimized electrical properties show high critical temperatures, T/sub C/, up to 92 K and high critical current densities, J/sub C/, up to 7/spl middot/10/sup 6/ A/cm/sup 2/ and surface microwave resistance, R/sub S/, less than 0.6 mOhm (at 10 GHz) at 77 K. The films with optimized surface smoothness show T/sub C/ up to 89 K, J/sub C/ up to 2/spl middot/10/sup 6/ A/cm/sup 2/ and they are free of any particles down to a size scale of 100 /spl Aring/.