MOCVD of high quality YBa2Cu3O7−δ thin films using a fluorinated barium precursor

Abstract MOCVD of superconducting YBa 2 Cu 3 O 7δ thin films using the novel fluorinated barium β-diketonate complex [Ba(TDFND) 2 ·tetraglyme] 1 in combination with [Y(TMHD) 3 ] 2 and [Cu(TMHD) 2 ] is reported. The Ba complex has a low melting point (72°C), is thermally stable to 200°C and allows reproducible and reliable film deposition even when maintained at 145°C for several weeks. Conversion of the fluoride to the oxide is achieved by in situ hydrolysis. Films deposited on SrTiO 3 (100) were characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, rocking curve, ac susceptibility and secondary ion mass spectrometry. Homogeneous layers of YBa 2 Cu 3 O 7−δ , ≈ 0.25 μm thick, were grown at ≈ 0.13 μm h −1 . The films are epitaxial with good c axis orientation. Critical temperatures T c are typically 91 K and critical current densities c (at 77 K) of ≈ 5 MA cm −2 are reported. SIMS results showing levels of residual fluorine do not exceed 250 ppm.