RELATION BETWEEN ELECTRICAL-PROPERTIES AND MICROSTRUCTURE OF YBA2CU3O7-X THIN-FILMS DEPOSITED BY SINGLE-TARGET OFF-AXIS SPUTTERING

The relationship between the deposition conditions and the structural and electrical properties of in situ superconducting YBa2Cu3O7-x thin films deposited by off-axis magnetron sputtering has been investigated . High-quality films have been produced with a transition temperature T-C (R=0) of 92 K, a critical current density J(C) (zero field) of 3.3 X10(7) A/cm(2) at 4.2 K and 4.8X10(6) A/cm(2) at 77 K, and a microwave surface resistance R(S) of 2.6X10(-6) Omega at 1.5 GHz and s 4.2 K wh ich rises to 8.3X10(-6) Omega at 77 K. Among the deposition conditions explored, substrate temperature was identified as the most influentia l in producing these high-quality films. A quantitative relationship w as established between substrate temperature and T-C, normal-state res istivity p, J(C), orientation distribution, x-ray-diffraction peak bro adening, lattice expansion, R(S), and penetration depth II. Increasing substrate temperature results in an increase in T-C, a decrease in p, an increase in J(C), an increase in grain size, an increase in the ra tio of c-axis- to a-axis-oriented grains, and a decrease in lambda. Th e deposition conditions of high substrate temperature and oxygen press ure, used to form films of the highest electrical and structural quali ty, also promote the formation of CuO precipitates of about 1 mu m in dimension, resulting from a slightly copper-rich stoichiometry.