A quasi-stoichiometric SiC-based fibre, has been prepared at a pyrolysis temperature of 1800 degrees C, from a boron-doped polycarbosilane precursor using an extrusion-chemical curing-pyrolysis procedure. The green fibre was rendered infusible by sequential curing with ozone and trimethylamine-borane adduct (O-3/Me3N:BH3). The fibre was characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, electron energy loss spectroscopy and Raman spectroscopy.