SiCf/SiC composite has a high potential for applications such as thermal protection systems due to its high oxidation resistance, high heat emissivity and low through-the-thickness (transverse) thermal conductivity, mainly if hollow fibers are used as reinforcement phase of the composite. PAN polymer is a precursor widely used and studied for developing high performance carbon fibers. Most commercial carbon fibers are basically derived from PAN polymer. In this work, the influence of the fiber specific mass on the morphology of SiC fiber obtained by conversion reactions from PAN oxidized fiber precursor was investigated. These oxidized fibers were obtained by controlling the time and temperature during the process of stabilization/oxidation.