YBa 2 Cu 3 O 7 - δ (YBaCuO) thin films were prepared in situ by cathodic sputtering of stoichiometric target onto LaAlO 3 or MgO single crystal substrates. After deposition some samples were cooled down quickly (hundreds degrees/min) till room temperature under 0.35 mbar or 1 bar of O 2 , in order to preserve the original oxygen content and the structure of the films during the in situ growth. Reference samples were cooled down slowly (∼ 3°C/min, 1 bar of O 2 ), at optimized conditions. The composition, electrical and magnetic properties and microstructure of YBaCuO films were studied ex situ at room temperature. Both slowly and rapidly cooled samples at 1 bar of O 2 show good physical properties with values of T c (ρ = 0) ; 87 K, surface resistance R s (measured at 77 K, 10 GHz) 1 m Ω and J c (T = 5 K, zero field) 2 10 7 A/cm 2 . The rapidly cooled sample at low oxygen pressure shows high T c value but significant degradation of R s is observed. Our direct oxygen content measurements using recently developed Ion Beam Analysis (IBA) techniques show that both kind of films are fully oxygenated (O 7 ± 0 . 3 ) YBaCuO compounds. The combination of X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) measurements indicates the majority presence, in the case of the rapidly cooled films, of a disordered tetragonal phase, with lattice parameters a = b = 3.86 and c= 11.690 , whereas for the slowly cooled samples the dominant structure is orthorhombic, with a = 3.82 , b = 3.88 and c = 11.686 . It is concluded that fully oxygenated YBaCuO tetragonal phase is growing during cathodic deposition.