Résumé : Rare-earth borocarbide superconductors have recently attracted the attention of researchers because of their intriguing superconducting and magnetic properties. In the present paper we report on the in situ synthesis of high-quality thin films of these materials (RE = Y, Er) using planar magnetron sputtering. Low-temperature STM tunnelling investigations were performed on films and single crystals. The STM results, together with d.c. transport measurements, give strong evidence of the weak-coupling BCS nature of these compounds. A discussion of the magnetic vortex structure and of the interplay of superconductivity and magnetism is also included.