[en] Flash lamp annealing of heteroepitaxial silicon carbide on silicon structures involves melting the silicon below the SiC layer but the faceted nature of the liquid-solid interface leads to unacceptable surface roughness. This letter describes a method of controlling melting by using a melt stop created at a controlled depth below the Si/SiC interface by implanting a high dose of carbon, which significantly increases the silicon melting temperature. Results confirm the effectiveness of this approach for increasing surface uniformity, making liquid phase processing compatible with standard device fabrication techniques