Thin films of lanthanum cuprate were grown on SrTiO3 substrates by pulsed laser deposition and made superconducting (Tc ∼ 38 K) through the process of post-deposition fluorination using elemental fluorine. A microstructural analysis showed that the [1?̄10] zone of the film grows parallel to the [100] zone of the SrTiO3, substrate, reducing the lattice mismatch from 37.5% to 2.4%, At the film-substrate interface there is an intermediate layer 3-4 nm thick and twin-related grains emanate from t...